Chapter 17

A solution when diluted with water and boiled, gives a white precipitate. On addition of excess of \(\mathrm{NH}_{4} \mathrm{Cl} /\) \(\mathrm{NH}_{4} \mathrm{OH}\), the volume of precipitate decreases, leaving behind a white gelatinous precipitate. Identify the precipitate which dissolves in \(\mathrm{NH}_{4} \mathrm{OH} / \mathrm{NH}_{4} \mathrm{Cl}\). (a) \(\mathrm{Al}(\mathrm{OH})_{3}\) (b) \(\mathrm{Ca}(\mathrm{OH})_{2}\) (c) \(\mathrm{Mg}(\mathrm{OH})_{2}\) (d) \(\mathrm{Zn}(\mathrm{OH})_{2}\)

In the following sequence of reactions, identify the end product (D). \(\mathrm{Na}_{2} \mathrm{CO}_{3} \stackrel{\mathrm{SO}_{2}}{\longrightarrow}(\mathrm{A}) \stackrel{\mathrm{Na}_{2} \mathrm{CO}_{3}}{\longrightarrow}(\mathrm{B})\) Elemental \(\mathrm{S} \stackrel{\Delta}{\longrightarrow}(\mathrm{C}) \stackrel{\mathrm{I}_{2}}{\longrightarrow}(\mathrm{D})\) (a) \(\mathrm{Na}_{2} \mathrm{SO}_{4}\) (b) \(\mathrm{Na}_{2} \mathrm{~S}_{4} \mathrm{O}_{6}\) (c) \(\mathrm{Na}_{2} \mathrm{~S}\) (d) \(\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\)

\(1.04 \mathrm{~g}\) of bleaching powder was made into a paste with water and then the volume was made upto 200 ml. \(25 \mathrm{ml}\) of this solution was found to oxidize \(13.4\) \(\mathrm{ml}\) of a standard solution of arsenic containing \(4.3 \mathrm{~g}\) \(\mathrm{Al}_{2} \mathrm{O}_{3}\) per litre. Find the percentage available chlorine in the sample. (a) \(31.7 \%\) (b) \(36.7 \%\) (c) \(41.7 \%\) (d) \(63.6 \%\)

A white, water-insoluble solid (A), is attacked by an acid, liberating a colourless, odourless gas (B), leaving a clear solution (C). The solution (C) gives a white precipitate (D) on addition of dilute \(\mathrm{H}_{2} \mathrm{SO}_{4}\), (C) gives a yellow precipitate (E) on addition of \(\mathrm{K}_{2} \mathrm{CrO}_{4}\) solution. Gas (B) bubbled through a suspension of \(\mathrm{CaCO}_{3}\) causesdis solution of that compound. Identify (E). (a) \(\mathrm{CaCrO}_{4}\) (b) \(\mathrm{BaCr}_{2} \mathrm{O}_{7}\) (c) \(\mathrm{BaCrO}_{4}\) (d) none of these

The aqueous solution of an inorganic compound \((\mathrm{X}\) ), gives a white precipitate with \(\mathrm{NH}_{4} \mathrm{OH}\), which does not dissolve in excess of \(\mathrm{NH}_{4} \mathrm{OH}\). This aqueous solution also gives white precipitate with \(\mathrm{AgNO}_{3}\) and the precipitate is soluble in dilute \(\mathrm{HNO}_{3} .\) Here \((\mathrm{X})\) is (a) \(\mathrm{AlCl}_{3}\) (b) \(\mathrm{AlBr}_{3}\) (c) AIN (d) \(\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}\)

Match the following: List I List II 1\. efflorescent (i) \(\mathrm{NaOH}\) 2\. deliquescent (ii) \(\mathrm{KOH}\) 3\. fusion mixture (iii) \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) and \(\mathrm{K}_{2} \mathrm{CO}_{3}\) 4\. washing soda (iv) \(\mathrm{Na}_{2} \mathrm{CO}_{3} .10 \mathrm{H}_{2} \mathrm{O}\) The correct matching is \(\begin{array}{llll}1 & 2 & 3 & 4\end{array}\) (a) (ii) (i) (iv) (iii) (b) (i) (ii) (iii) (iv) (c) (ii) (i) (iii) (iv) (d) (i) (iii) (iv) (ii)

The major role of fluorspar \(\left(\mathrm{CaF}_{2}\right)\) which is added in small quantities in the electrolytic reduction of alumina dissolved in fused cryolite \(\left(\mathrm{Na}_{3} \mathrm{AlF}_{6}\right)\) is 1\. as a catalyst 2\. to make the fused mixture very conducting 3\. to lower the temperature of melt 4\. to decrease the rate of oxidation of carbon at the anode (a) 2,3 (b) 1,2 (c) \(2,3,4\) (d) 3,4

In the following sequence of reactions. Identify (E)? \(\mathrm{Na}_{2} \mathrm{CO}_{3}+\mathrm{H}_{2} \mathrm{O}+\mathrm{CO}_{2} \longrightarrow(\mathrm{A}) \stackrel{\Delta, \mathrm{ZnCl}_{2}}{\longrightarrow}\) \((\mathrm{B}) \stackrel{\Delta}{\longrightarrow}(\mathrm{C})+(\mathrm{D}) \uparrow \stackrel{\mathrm{NaOH}}{\longrightarrow}(\mathrm{E})\) (a) \(\mathrm{NaHCO}_{3}\) (b) \(\mathrm{Na}_{2} \mathrm{O}_{2}\) (c) \(\mathrm{Na}_{2} \mathrm{ZnO}_{2}\) (d) \(\mathrm{ZnCO}_{3}\)

The pair of compounds which cannot exist together in aqueous solution is 1\. \(\mathrm{NaH}_{2} \mathrm{PO}_{4}\) and \(\mathrm{Na}_{2} \mathrm{HCO}_{3}\) 2\. \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) and \(\mathrm{NaHCO}_{3}\) 3\. \(\mathrm{NaOH}\) and \(\mathrm{NaH}_{2} \mathrm{PO}_{4}\) 4\. \(\mathrm{NaHCO}_{3}\) and \(\mathrm{NaOH}\) (a) \(1,2,3\) (b) 3,4 (c) 1,4 (d) 2,3

Consider the following reactions: 1\. \(2 \mathrm{Na}+2 \mathrm{H}_{2} \mathrm{O} \longrightarrow 2 \mathrm{NaOH}+\mathrm{H}_{2}\) 2\. \(2 \mathrm{NaOH}+\mathrm{Cl}_{2} \longrightarrow \mathrm{NaCl}+\mathrm{NaOCl}+\mathrm{H}_{2} \mathrm{O}\) 3\. \(4 \mathrm{OH}^{-} \longrightarrow \mathrm{O}_{2}+2 \mathrm{H}_{2} \mathrm{O}+4 \mathrm{e}^{-}\) 4\. \(2 \mathrm{Cl} \longrightarrow \mathrm{Cl}_{2}^{2}+2 \mathrm{e}\) In the diaphragm cell used for the electrolysis of brine, the reactions that occur would include (a) \(2,3,4\) (b) \(1,3,4\) (c) \(1,2,3\) (d) \(1,2,4\)

When brine solution is saturated with \(\mathrm{NH}_{3}\) and \(\mathrm{CO}_{2}\) a slightly alkaline white sodium salt (A) is formed which has \(\mathrm{pH}\) of nearly \(8.4\). (A) on heating liberates a gas (B) leaving a highly alkaline residue (C) of \(\mathrm{pH}\) nearly 10 to 11. Gas (B) is colourless and turns a solution of \(\mathrm{Ca}(\mathrm{OH})_{2}\) milky. Identify \((\mathrm{B})\). (a) \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) (b) \(\mathrm{NaHCO}_{3}\) (c) \(\mathrm{Na}_{2} \mathrm{~S}\) (d) \(\mathrm{Na}_{2} \mathrm{SO}_{4}\)

Consider the following statements: 1\. \(\mathrm{Cs}^{+}\)ion is more highly hydrated than other alkali metal ions 2\. Among the alkali metals \(\mathrm{Li}\), \(\mathrm{Na}, \mathrm{K}\) and \(\mathrm{Rb}, \mathrm{Li}\) has the higher melting point 3\. Among the alkali metals, only Li form a stable nitride by direct combination (a) 1 and 3 are correct (b) 2 and 3 are correct (c) 1,2 and 3 are correct (d) 1 and 2 are correct

Metal \(\mathrm{X}\) on heating in nitrogen gas gives Y.Y on treatment with \(\mathrm{H}_{2} \mathrm{O}\) gives a colourless gas which when passed through \(\mathrm{CuSO}_{4}\) solution gives a blue colour. \(Y\) is (a) \(\mathrm{MgO}\) (b) \(\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}\) (c) \(\mathrm{Mg}_{3} \mathrm{~N}_{2}\) (d) \(\mathrm{NH}_{3}\)

Highly pure dilute solution of sodium in liquid ammonia 1\. shows blue colour 2\. exhibits electrical conductivity 3\. produces sodium amide 4\. produces hydrogen gas (a) 1,2 (b) \(1,2,3\) (c) \(2,3,4\) (d) all of these

Out of the following metals, those that cannot be obtained by electrolysis of the aqueous solution of their salts are 1\. Ag 2\. \(\mathrm{Mg}\) 3\. \(\mathrm{Cu}\) 4\. Al (a) 2,4 (b) 2,3 (c) 1,4 (d) all

Match the following: List-I List-II 1\. Beryl (i) \(\mathrm{KCl} \cdot \mathrm{MgCl}_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O}\) 2\. Carnalite (ii) \(\mathrm{MgCO}_{3}\) 3\. Asbestos (iii) \(3 \mathrm{BeO} \cdot \mathrm{Al}_{2} \mathrm{O}_{3} \cdot 6 \mathrm{SiO}_{2}\) 4\. Magnesite (iv) \(\mathrm{Ca}_{2} \mathrm{Mg}_{5} \mathrm{Si}_{8} \mathrm{O}_{22}(\mathrm{OH})_{2}\) (v) \(\mathrm{CaSO}_{4} \cdot 2 \mathrm{H}_{2} \mathrm{O}\) The correct matching is: \(\begin{array}{llll}1 & 2 & 3 & 4\end{array}\) (a) (iii) (iv) (i) (ii) (b) (iv) (iii) (ii) (i) (c) (iii) (i) (iv) (ii) (d) (iii) (i) (ii) (iv)

Select the correct statement(s): (a) \(\mathrm{BaSO}_{4}\) is soluble in water (b) \(\mathrm{Ba}(\mathrm{OH})_{2}\) is soluble in water (c) \(\mathrm{MgSO}_{4}\) is soluble in water (d) \(\mathrm{CaF}_{2}\) is soluble in water

Select the incorrect statement(s): (a) Milk of magnesia is an aqueous solution of \(\mathrm{Mg}(\mathrm{OH})_{2}\) (b) \(\mathrm{KOH}\) is a weaker base than \(\mathrm{NaOH}\) (c) \(\mathrm{CaO}_{2}\) is less stable than \(\mathrm{MgO}_{2}\) (d) \(\mathrm{Mg}^{2+}\) ions are precipitated with the addition of \(\mathrm{NH}_{4} \mathrm{OH}\) in the presence of \(\mathrm{NH}_{4} \mathrm{Cl}\)

Select the correct statement(s) are: (a) \(\mathrm{Na}_{2} \mathrm{CO}_{3} \cdot \mathrm{NaHCO}_{3} \cdot 2 \mathrm{H}_{2} \mathrm{O}\) is a mineral called trona. (b) \(\mathrm{Li}_{2} \mathrm{CO}_{3}\) and \(\mathrm{MgCO}_{3}\) both are thermally stable (c) \(\mathrm{Li}_{2} \mathrm{CO}_{3}\) is only sparingly soluble in water and no LiHCO \(_{3}\) has been isolated. (d) \(\mathrm{K}_{2} \mathrm{CO}_{3}\) cannot be made by a method similar to the ammonia-soda process.

Which of the following statement(s) is/are true? (a) Stability of alkali metal peroxide increases with increase in atomic number (b) Hydration energy of \(\mathrm{AgF}\) is higher than its lattice energy (c) Anhydrous \(\mathrm{MgCl}_{2}\) cannot be prepared by direct heating of \(\mathrm{MgCl}_{2} .6 \mathrm{H}_{2} \mathrm{O}\) (d) The milk of magnesia used as antacid is chemically \(\mathrm{MgO}+\mathrm{MgCl}_{2}\)

Select the correct statement(s): (a) Be dissolves in alkali forming \(\left[\mathrm{Be}(\mathrm{OH})_{4}\right]^{2-}\) (b) \(\mathrm{BeF}_{2}\) forms complex ion with \(\mathrm{NaF}\) in which \(\mathrm{Be}\) goes with cation (c) \(\mathrm{BeCO}_{3}\) is kept in the atmosphere of \(\mathrm{CO}_{2}\) since, it is least thermally stable (d) \(\mathrm{BeF}_{2}\) forms complex ion with \(\mathrm{NaF}\) in which Be goes with anion.

The pair of compounds which cannot exist together in aqueous solution is (a) \(\mathrm{NaH}_{2} \mathrm{PO}_{4}\) and \(\mathrm{Na}_{2} \mathrm{HCO}_{3}\) (b) \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) and \(\mathrm{NaHCO}_{3}\) (c) \(\mathrm{NaOH}\) and \(\mathrm{NaH}_{2} \mathrm{PO}_{4}\) (d) \(\mathrm{NaHCO}_{3}\) and \(\mathrm{NaOH}\)

Nitrate of which of the following elements can be converted into their oxides on heating? (a) \(\mathrm{Na}\) (b) \(\mathrm{Li}\) (c) \(\mathrm{Mg}\) (d) \(\mathrm{Rb}\)

Sodium sulphate is soluble in water whereas barium sulphate is sparingly soluble because (a) The hydration energy of sodium sulphate is more than its lattice energy (b) The lattice energy of barium sulphate is more than its hydration energy (c) The lattice energy has no role to play in solubility (d) The hydration energy of sodium sulphate is less than its lattice energy.

Which of the following oxides have rock salt structure with coordination number \(6: 6\). (a) \(\mathrm{MgO}\) (b) \(\mathrm{CaO}\) (c) \(\mathrm{SrO}\) (d) \(\mathrm{B}_{2} \mathrm{O}_{3}\)

\(\mathrm{Mg}\) and \(\mathrm{Zn}\) have following resemblance: (a) Both of them can be used as electrodes (b) \(\mathrm{MgO}\) and \(\mathrm{ZnO}\) are amphoteric. (c) Both of them can be used to prevent corrosion (d) \(\mathrm{MgCO}_{3}, \mathrm{ZnCO}_{3}\) both on heating give their oxides.

Out of the following the correct statement is/are: (a) \(\mathrm{BeCl}_{2}\) is an electron deficient molecule (b) \(\mathrm{BeCl}_{2}\) is a covalent compound (c) The hybridisation state of \(\mathrm{Be}\) in \(\mathrm{BeCl}_{2}\) is \(\mathrm{sp}^{3}\) (d) \(\mathrm{BeCl}_{2}\) can form dimer

Gypsum on heating gives: (a) \(\mathrm{CaS}+\mathrm{O}_{2}\) (b) \(\mathrm{CaO}+\mathrm{SO}_{3}\) (c) \(\mathrm{CaSO}_{4} \cdot 1 / 2 \mathrm{H}_{2} \mathrm{O}\) (d) \(\mathrm{CaSO}_{4}\)

Which of the following metals are extracted by using \(\mathrm{Al}\) as a reducing agent? (a) \(\mathrm{W}\) from \(\mathrm{WO}_{3}\) (b) \(\mathrm{Mg}\) from \(\mathrm{MgO}\) (c) Na from \(\mathrm{Na}_{2} \mathrm{O}\) (d) \(\mathrm{Cr}\) from \(\mathrm{Cr}_{2} \mathrm{O}_{3}\)

Which is true about beryllium? (a) \(\mathrm{Be}(\mathrm{OH})_{2}\) is basic in nature only. (b) Beryllium halides are electron deficient. (c) Aqueous solution of \(\mathrm{BeCl}_{2}\) is acidic. (d) It forms unusual carbide \(\mathrm{Be}_{2} \mathrm{C}\).

Element A burns in nitrogen to give an ionic compound B. Compound B reacts with water to give \(\mathrm{C}\) and D. A solution of \(\mathrm{C}\) becomes 'milky' on bubbling carbon dioxide. Here the element (A) is (a) \(\mathrm{Mg}\) (b) \(\mathrm{Na}\) (c) \(\mathrm{Ca}\) (d) \(\mathrm{K}\)

When \(16.8 \mathrm{~g}\) of white solid \(\mathrm{X}\) were heated, \(4.4 \mathrm{~g}\) of acid gas A that turned lime water milky was driven off together with \(1.8 \mathrm{~g}\) of a gas \(\mathrm{B}\) which condensed to a colourless liquid. The solid that remained, \(Y\), dissolved in water to give an alkaline solution, which with excess barium chloride solution gave a white precipitate \(Z\). The precipitate effervesced with acid giving off carbon dioxide. Identify A, B and Y and write down the equation for the thermal decomposition of \(\mathrm{X}\). Here \((\mathrm{X})\) is (a) \(\mathrm{KHCO}_{3}\) (b) \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) (c) \(\mathrm{NH}_{4} \mathrm{HCO}_{3}\) (d) \(\mathrm{NaHCO}_{3}\)

When \(16.8 \mathrm{~g}\) of white solid \(\mathrm{X}\) were heated, \(4.4 \mathrm{~g}\) of acid gas A that turned lime water milky was driven off together with \(1.8 \mathrm{~g}\) of a gas \(\mathrm{B}\) which condensed to a colourless liquid. The solid that remained, \(Y\), dissolved in water to give an alkaline solution, which with excess barium chloride solution gave a white precipitate \(Z\). The precipitate effervesced with acid giving off carbon dioxide. Identify A, B and Y and write down the equation for the thermal decomposition of \(\mathrm{X}\). Here (A) and (B) are respectively: (a) \(\mathrm{CO}_{2}\) and \(\mathrm{N}_{2}\) (b) \(\mathrm{CO}_{2}\) and \(\mathrm{H}_{2}\) (c) \(\mathrm{CO}_{2}\) and \(\mathrm{H}_{2} \mathrm{O}\) (d) \(\mathrm{CO}_{2}\) and \(\mathrm{NH}_{3}\)

When \(16.8 \mathrm{~g}\) of white solid \(\mathrm{X}\) were heated, \(4.4 \mathrm{~g}\) of acid gas A that turned lime water milky was driven off together with \(1.8 \mathrm{~g}\) of a gas \(\mathrm{B}\) which condensed to a colourless liquid. The solid that remained, \(Y\), dissolved in water to give an alkaline solution, which with excess barium chloride solution gave a white precipitate \(Z\). The precipitate effervesced with acid giving off carbon dioxide. Identify A, B and Y and write down the equation for the thermal decomposition of \(\mathrm{X}\). Here \((\mathrm{Y})\) and \((\mathrm{Z})\) are respectively: (a) \(\mathrm{NaHCO}_{3}\) and \(\mathrm{BaHCO}_{3}\) (b) \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) and \(\mathrm{BaCO}_{3}\) (c) \(\mathrm{NaOH}\) and \(\mathrm{BaCO}_{3}\) (d) \(\mathrm{K}_{2} \mathrm{CO}_{3}\) and \(\mathrm{BaCO}_{3}\)

$$ \begin{aligned} &\text { Match the following }\\\ &\begin{array}{ll} \hline \text { Column-I} \text {Column-II } \\ \hline \begin{array}{ll} \text { (a) } \mathrm{Na}_{2} \mathrm{CO}_{3} & \text { (p) SO }_{2} \text { absorber } \\ \text { (b) } \mathrm{Na}_{2} \mathrm{SO}_{3} & \text { (q) Detergent } \\ \text { (c) } \mathrm{NaOH} & \text { (r) Glass } \\ \text { (d) } \mathrm{NaOCl} & \text { (s) Bleach } \\ \hline \end{array} \end{array} \end{aligned} $$

$$ \begin{aligned} &\text { Match the following }\\\ &\begin{array}{ll} \hline \text { Column-I } & \text { Column-II } \\ \hline \text { (a) Castner Kellner } & \text (p) \mathrm{MgCl}_{2} .5 \mathrm{MgO} \cdot \mathrm{xH}_{2} \mathrm{O} \\ \text { cell } & \text { (q) } \mathrm{K}_{2} \mathrm{CO}_{3} \\ \text { (b) Pearl ash } & \text { (r) Manufacture of } \mathrm{NaHCO}_{3} \\ \text { (c) Solvay's process } & \text { (s) Manufacture of } \mathrm{NaOH} \\\ \text { (d) Sorel's cement } & \text { (s) } \\ \hline \end{array} \end{aligned} $$

$$ \begin{aligned} &\text { Match the following }\\\ &\begin{array}{ll} \text { Column-I } & \text { Column-II } \\ \hline \begin{array}{ll} \text { (a) Magnesia } & \text { (p) } \mathrm{MgSO}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O} \\ \text { (b) Epsom salt } & \text { (q) } \mathrm{MgO} \\ \text { (c) Anhydrone } & \text { (r) } \mathrm{CaH}_{2} \\ \text { (d) Hydrolith } & \text { (s) } \mathrm{Mg}\left(\mathrm{ClO}_{4}\right)_{2} \end{array} \\ \hline \end{array} \end{aligned} $$

$$ \begin{aligned} &\text { Match the following }\\\ &\begin{array}{ll} \hline \text { List-I } & \text { List-II } \\ \hline \text { (a) Aqueous solution of (p) Anhydrone } \\ \mathrm{NaOCl} & \text { (q) Javelle water } \\ \text { (b) } \mathrm{KClO}_{3} & \text { (r) Euchlorine } \\ \begin{array}{ll} \text { (c) } \mathrm{Mg}\left(\mathrm{ClO}_{4}\right)_{2} & \text { (s) Berthelot's salt } \\ \text { (d) } \mathrm{Cl}_{2} \text { and } \mathrm{ClO}_{2} \text { mixture } & \text { (s) } \\ \hline \end{array} \end{array} \end{aligned} $$

\(\mathrm{KO}_{2}\) (potassium super oxide) is used in oxygen cylinders in space and submarines because it (a) produces ozone (b) absorbs \(\mathrm{CO}_{2}\) (c) absorbs \(\mathrm{CO}_{2}\) and increase \(\mathrm{O}_{2}\) contents (d) eliminates moisture

A metal \(\mathrm{M}\) readily forms water soluble sulphate \(\mathrm{MSO}_{4}\), water insoluble hydroxide \(\mathrm{M}(\mathrm{OH})_{2}\) and oxide MO which becomes inert on heating. The hydroxide is soluble in \(\mathrm{NaOH}\). \(\mathrm{M}\) is (a) \(\mathrm{Mg}\) (b) \(\mathrm{Sr}\) (c) \(\mathrm{Be}\) (d) \(\mathrm{Ca}\)

In curing cement plasters, water is sprinkled from time to time. This helps in [2003] (a) hydrating sand gravel mixed with cement (b) keeping it cool (c) converting sand into silicic acid (d) developing interlocking needle like crystals of hydrated silicates

The substance not likely to contain \(\mathrm{CaCO}_{3}\) is [2003] (a) sea shells (b) calcined gypsum (c) dolomite (d) a marble statue

Several blocks of magnesium are fixed to the bottom of a ship to (a) keep away the sharks (b) prevent action of water and salt (c) make the ship lighter (d) prevent puncturing by under sea rocks

Beryllium and aluminium exhibit many properties which are similar. But the two elements differ in [2004] (a) forming polymeric hydrides (b) forming covalent halides (c) exhibiting maximum covalency in compounds (d) exhibiting amphoteric nature in their oxides.

Heating an aqueous solution of aluminium chloride to dryness will give (a) \(\mathrm{AlCl}_{3}\) (b) \(\mathrm{Al}_{2} \mathrm{Cl}_{3}\) (c) \(\mathrm{Al}(\mathrm{OH}) \mathrm{Cl}_{2}\) (d) \(\mathrm{Al}_{2} \mathrm{Cl}_{6}\)

Which of the following on thermal - decomposition yields a basic as well as an acidic oxide? (a) \(\mathrm{CaCO}_{3}\) (b) \(\mathrm{NaNO}_{3}\) (c) \(\mathrm{KClO}_{3}\) (d) \(\mathrm{NH}_{4} \mathrm{NO}_{3}\)

The mainoxides formed on combusting of Li, Na and \(\mathrm{K}\) in excess of air are respectively? [2016] (a) \(\mathrm{LiO}_{2} \mathrm{Na}_{2} \mathrm{O}_{2}\) and \(\mathrm{K}_{2} \mathrm{O}\) (b) \(\mathrm{Li}_{2} \mathrm{O}_{2} \mathrm{Na}_{2} \mathrm{O}_{2}\) and \(\mathrm{KO}_{2}\) (c) \(\mathrm{Li}_{2} \mathrm{O} \mathrm{Na}_{2} \mathrm{O}_{2}\) and \(\mathrm{KO}_{2}\) (d) \(\mathrm{Li}_{2} \mathrm{O} \mathrm{Na}_{2} \mathrm{O}\) and \(\mathrm{KO}_{2}\)