Chapter 8

Which of these can not be a bronsted acid? (a) \(\mathrm{HCO}_{3}^{-}\) (b) \(\mathrm{HCOO}^{-}\) (c) \(\mathrm{H}_{2} \mathrm{PO}_{3}^{-}\) (d) \(\mathrm{H}_{3} \mathrm{O}^{+}\)

Conjugate acid of \(\mathrm{NH}_{2}^{-}\)is (a) \(\mathrm{NH}_{4}^{+}\) (b) \(\mathrm{NH}_{3}\) (c) \(\mathrm{NH}_{2}\) (d) \(\mathrm{NH}\)

The ionization constant of phenol is higher than that of ethanol because (a) phenoxide ion is bulkier than ethoxide (b) phenoxide ion is stronger base than ethoxide (c) phenoxide ion is stabilized through delocalization (d) phenoxide ion is less stable than ethoxide

In \(\mathrm{HS}^{-}, \mathrm{I}, \mathrm{RNH}_{2}\) and \(\mathrm{NH}_{3}\) order of proton accepting tendency will be (a) \(\mathrm{I}^{->} \mathrm{NH}_{3}>\mathrm{RNH}_{2}>\mathrm{HS}^{-}\) (b) \(\mathrm{HS}^{-}>\mathrm{RNH}_{2}>\mathrm{NH}_{3}>\mathrm{I}^{-}\) (c) \(\mathrm{RNH}_{2}>\mathrm{NH}_{3}>\mathrm{HS}^{-}>\mathrm{I}^{-}\) (d) \(\mathrm{NH}_{3}>\mathrm{RNH}_{2}>\mathrm{HS}^{-}>\mathrm{I}^{-}\)

Which one of the following orders of acid strength if correct? (a) \(\mathrm{RCOOH}>\mathrm{HC} \equiv \mathrm{CH}>\mathrm{HOH}>\mathrm{ROH}\) (b) \(\mathrm{RCOOH}>\mathrm{ROH}>\mathrm{HOH}>\mathrm{HC} \equiv \mathrm{CH}\) (c) \(\mathrm{RCOOH}>\mathrm{HOH}>\mathrm{ROH}>\mathrm{HC} \equiv \mathrm{CH}\) (d) \(\mathrm{RCOOH}>\mathrm{HOH}>\mathrm{HC} \equiv \mathrm{CH}>\mathrm{ROH}\)

Which one of the following compounds is not a protonic acid? (a) \(\mathrm{SO}_{2}(\mathrm{OH})_{2}\) (b) \(\mathrm{B}(\mathrm{OH})_{3}\) (c) \(\mathrm{PO}(\mathrm{OH})_{3}\) (d) \(\mathrm{SO}(\mathrm{OH})_{2}\)

What is the correct relationship between the pHs of isomolar solutions of sodium oxide \(\left(\mathrm{pH}_{1}\right)\), sodium sulphide \(\left(\mathrm{pH}_{2}\right)\), sodium selenide \(\left(\mathrm{pH}_{3}\right)\) and sodium telluride \(\left(\mathrm{pH}_{4}\right)\) ? (a) \(\mathrm{pH}_{1}>\mathrm{pH}_{2}=\mathrm{pH}_{3}>\mathrm{pH}_{4}\) (b) \(\mathrm{pH}_{1}<\mathrm{pH}_{2}<\mathrm{pH}_{3}<\mathrm{pH}_{4}\) (c) \(\mathrm{pH}_{1}<\mathrm{pH}_{2}<\mathrm{pH}_{3}=\mathrm{pH}_{4}\) (d) \(\mathrm{pH}_{1}>\mathrm{pH}_{2}>\mathrm{pH}_{3}>\mathrm{pH}_{4}\)

Which of the following pairs constitutes buffer solutions? (a) \(\mathrm{HNO}_{3}\) and \(\mathrm{NH}_{4} \mathrm{NO}_{3}\) (b) \(\mathrm{HCl}\) and \(\mathrm{KCl}\) (c) \(\mathrm{HNO}_{2}\) and \(\mathrm{NaNO}_{2}\) (d) \(\mathrm{NaOH}\) and \(\mathrm{NaCl}\)

The \(\mathrm{H}^{+}\)ion concentration of a solution is \(1 \mathrm{~mol} \mathrm{~L}^{-1}\). Its \(\mathrm{pH}\) is (a) \(0.1\) (b) \(1.5\) (c) \(1.0\) (d) 0

Which of the following is a tribasic acid? (a) \(\mathrm{H}_{3} \mathrm{PO}_{4}\) (b) \(\mathrm{H}_{3} \mathrm{PO}_{3}\) (c) \(\mathrm{H}_{3} \mathrm{PO}_{2}\) (d) \(\mathrm{HPO}_{3}\)

In which of the following acid-base titration, \(\mathrm{pH}\) is greater than 8 at equivalence point? (a) acetic acid vs ammonia (b) acetic acid vs sodium hydroxide (c) hydrochloric acid vs ammonia (d) hydrochloric acid vs sodium hydroxide

Which one of the following is not a buffer solution? (a) \(0.8 \mathrm{M} \mathrm{H}_{2} \mathrm{~S}+0.8 \mathrm{M} \mathrm{KHS}\) (b) \(2 \mathrm{M} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}+2 \mathrm{M} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{3}{\underline{\phantom{xx}}}^{+} \mathrm{Br}^{-}\) (c) \(3 \mathrm{M} \mathrm{H}_{2} \mathrm{CO}_{3}+3 \mathrm{M} \mathrm{KHCO}_{3}\) (d) \(0.05 \mathrm{M} \mathrm{KCIO}_{4}+0.05 \mathrm{M} \mathrm{HClO}_{4}\)

The \(\mathrm{pH}\) of pure water at \(80^{\circ} \mathrm{C}\) will be \((\mathrm{a})=7\) (b) \(<7\) (c) \(>7\) (d) none of these

A centinormal solution of a monobasic acid is \(100 \%\) ionized. Its \(\mathrm{pH}\) is (a) 2 (b) 4 (c) 3 (d) 1

When a buffer solution of \(\mathrm{CH}_{3} \mathrm{COONa}\) and \(\mathrm{CH}_{3} \mathrm{COOH}\) is diluted with water then (a) \(\mathrm{H}^{+}\)ion concentration increases (b) \(\mathrm{H}^{+}\)ion concentration decreases (c) \(\mathrm{H}^{+}\)ion concentration remains constant (d) \(\mathrm{CH}_{3} \mathrm{COO}^{-}\)ion concentration increases

Which of the following would produce a buffer solution when mixed in equal volume? (a) \(1 \mathrm{M} \mathrm{CH}_{3} \mathrm{COOH}\) and \(0.5 \mathrm{M} \mathrm{NaOH}\) (b) \(1 \mathrm{M} \mathrm{CH}_{3} \mathrm{COOH}\) and \(0.5 \mathrm{M} \mathrm{HCl}\) (c) \(1 \mathrm{M} \mathrm{NH}_{4} \mathrm{OH}\) and \(0.5 \mathrm{M} \mathrm{NaOH}\) (d) \(1 \mathrm{M} \mathrm{NH}_{4} \mathrm{Cl}\) and \(0.5 \mathrm{M} \mathrm{HCl}\)

At \(25^{\circ} \mathrm{C}\) the \(\mathrm{pH}\) value of a solution is 6, the solution is (a) neutral (b) acidic (c) alkaline (d) basic

The \(\mathrm{pH}\) of \(\mathrm{N} / 10 \mathrm{HCl}\) is (a) 3 (b) 4 (c) 2 (d) 1

Which one of the following statement is correct? (a) Bronsted-Lowry theory could not explain the acidic nature of \(\mathrm{BCl}_{3}\) (b) the \(\mathrm{pH}\) of \(0.01 \mathrm{M} \mathrm{NaOH}\) solution is 2 (c) the ionic product of water at \(25^{\circ} \mathrm{C}\) is \(10^{-10} \mathrm{~mol}^{2} \mathrm{~L}^{-2}\) (d) the \(\mathrm{pH}\) of a solution can be calculated using the equation \(\mathrm{pH}=\log \left[\mathrm{H}^{+}\right]\)

Which of the following can act like a buffer? (a) \(\mathrm{CH}_{3} \mathrm{COOH}+\mathrm{CH}_{3} \mathrm{COONa}\) (b) \(\mathrm{NH}_{4} \mathrm{ND}_{3}+\mathrm{NH}_{4} \mathrm{OH}\) (c) \(50 \mathrm{ml} 0.1 \mathrm{~m} \mathrm{NaCN}+30 \mathrm{ml} 0.1 \mathrm{~m} \mathrm{HCl}\) (d) All of these

Which one of the following statements is not correct? (a) \(\mathrm{Cl}-\) is a lewis acid (b) the \(\mathrm{pH}\) of \(10^{-8} \mathrm{M} \mathrm{HCl}\) solution is less than \(7 .\) (c) the ionic product of water at \(25^{\circ} \mathrm{C}\) is \(10^{-14}\) \(\mathrm{mol}^{2} \mathrm{~L}^{-2}\) (d) Bronsted-Lowry theory could not explain the acidic character of \(\mathrm{AlCl}_{3}\).

\(\mathrm{NH}_{4} \mathrm{Cl}\) solution is (a) neutral (b) acidic (c) basic (d) amphoteric

In the titration of iodine against hype the indicator used is (a) starch (b) potassium ferricyanide (c) methyl orange (d) methyl red

The indicator used for titration of weak base and strong acid is (a) thymol blue (b) methyl orange (c) phenolpthalein (d) fluorescein

The correct order of relative acidity is (a) \(\mathrm{HClO}>\mathrm{HClO}_{2}>\mathrm{HClO}_{3}>\mathrm{HClO}_{4}\) (b) \(\mathrm{HClO}_{4}>\mathrm{HClO}_{3}>\mathrm{HClO}_{2}>\mathrm{HClO}\) (c) \(\mathrm{HClO}>\mathrm{HClO}_{4}>\mathrm{HClO}_{2}>\mathrm{HClO}_{3}\) (d) \(\mathrm{HClO}_{3}>\mathrm{HClO}_{2}>\mathrm{HClO}_{4}>\mathrm{HClO}\)

\(\mathrm{CH}_{3} \mathrm{COOH}\) is weaker acid than \(\mathrm{H}_{2} \mathrm{SO}_{4}\). It is due to (a) more ionization (b) less ionization (c) covalent bond (d) electrovalent bond

Which one of the following pair show buffer's solution? (a) \(\mathrm{NaCl}+\mathrm{NaOH}\) (b) \(\mathrm{CH}_{3} \mathrm{COONa}+\mathrm{CH}_{3} \mathrm{COOH}\) (c) \(\mathrm{CH}_{3} \mathrm{COOH}+\mathrm{CH}_{3} \mathrm{COONH}_{4}\) (d) \(\mathrm{H}_{2} \mathrm{SO}_{4}+\mathrm{CuSO}_{4}\)

Which of the following is correct? (a) the \(\mathrm{pH}\) of one litre solution containing \(0.49 \mathrm{~g}\) of \(\mathrm{H}_{2} \mathrm{SO}_{4}\) is \(2.0\) (b) the conjugate base of \(\mathrm{H}_{2} \mathrm{~S}\) is \(\mathrm{S}^{2-}\) (c) \(\mathrm{BF}_{3}\) is lewis base (d) phenolphthalein is colourless in basic medium.

At \(90^{\circ} \mathrm{C}\), pure water has \(\left[\mathrm{H}_{3} \mathrm{O}^{+}\right] 10^{-6}\) mole litre \(^{-1}\). What is the value of \(K_{w}\) at \(90^{\circ} \mathrm{C}\) ? (a) \(10^{-8}\) (b) \(10^{-6}\) (c) \(10^{-12}\) (d) \(10^{-14}\)

Of the given anions, the strongest bronsted base is (a) \(\mathrm{ClO}_{4}^{-}\) (b) \(\mathrm{ClO}_{3}^{-}\) (c) \(\mathrm{ClO}_{2}^{-}\) (d) \(\mathrm{ClO}^{-}\)

A acidic buffer solution can be prepared by mixing the solutions of (a) sodium chloride and sodium hydroxide (b) sulphuric acid and sodium sulphate (c) ammonium chloride and ammonium hydroxide (d) ammonium acetate and acetic acid

Molten sodium chloride conducts electricity due to the presence of (a) free ions (b) free molecules (c) free electrons (d) atoms of sodium and chlorine

For the reaction \(\mathrm{H}_{2}(\mathrm{~g})+\mathrm{I}_{2}(\mathrm{~g}) \leftrightarrow 2 \mathrm{HI}(\mathrm{g})\) the equilib- rium constant \(\mathrm{K}_{\mathrm{p}}\) changes with (a) catalyst (b) temperature (c) total pressure (d) the amounts of \(\mathrm{H}_{2}\) and \(\mathrm{I}_{2}\) present

Pure ammonia is placed in a vessel at a temperature where its dissociation constant \((\alpha)\) is appreciable. At equilibrium (a) \(\alpha\) does not change with pressure (b) concentration of \(\mathrm{NH}_{2}\) does not change with pressure (c) concentration of hydrogen is less than that of nitrogen (d) \(\mathrm{K}\) does not changes significantly with pressure

The best indicator for detection of end point in titration of a weak acid and strong base is (a) methyl red ( 5 to 6 ) (b) methyl orange ( 3 to 4 ) (c) phenolphthalein \((8\) to \(9.6)\) (d) bromothymol blue ( 6 to \(7.5\) )

The conjugate acid of \(\mathrm{NH}_{2}^{-}\)is (a) \(\mathrm{NH}_{4}^{+}\) (b) \(\mathrm{NH}_{3}\) (c) \(\mathrm{NH}_{2} \mathrm{OH}\) (d) \(\mathrm{N}_{2} \mathrm{H}_{4}\)

The \(\mathrm{pH}\) of the neutralization point of \(0.1 \mathrm{~N}\) ammonium hydroxide with \(0.1 \mathrm{NHCl}\) is (a) 1 (b) 6 (c) 9 (d) 7

The compound whose \(0.1 \mathrm{M}\) solution is basic is (a) ammonium acetate (b) ammonium sulphate (c) sodium acetate (d) ammonium chloride

Amongst the following hydroxides, the one which has the lowest value of \(K_{s p}\) at ordinary temperature (about \(25^{\circ} \mathrm{C}\) ) is (a) \(\mathrm{Mg}(\mathrm{OH})_{2}\) (b) \(\mathrm{Ca}(\mathrm{OH})_{2}\) (c) \(\mathrm{Ba}(\mathrm{OH})_{2}\) (d) \(\mathrm{Be}(\mathrm{OH})_{2}^{2}\)

Fear or excitement, generally causes one to breathe rapidly and it results in the decrease of \(\mathrm{CO}_{2}\) concentration in blood. In what way will it change the \(\mathrm{pH}\) of blood? (a) \(\mathrm{pH}\) will increase (b) \(\mathrm{pH}\) will decrease (c) no change (d) \(\mathrm{pH}\) will adjust to 7

A buffer solution can be prepared from a mixture of 1\. sodium acetate and acetic acid in water 2\. sodium acetate and hydrochloric acid in water 3\. ammonia and ammonium chloride in water 4\. ammonia and sodium hydroxide in water. (a) \(1,3,4\) (b) \(2,3,4\) (c) \(1,2,4\) (d) \(1,2,3\)

Which among the following acts as a basic buffer solution? (a) \(\mathrm{NH}_{4} \mathrm{Cl}+\mathrm{NH}_{4} \mathrm{OH}\) (b) \(\mathrm{NaCl}+\mathrm{NaOH}\) (c) \(\mathrm{NH}_{4} \mathrm{Cl}+\mathrm{CH}_{3} \mathrm{COOH}\) (d) \(\mathrm{CH}_{3} \mathrm{COONa}+\mathrm{CH}_{3} \mathrm{COOH}\)

Conjugate base of hydrazoic acid is (a) \(\mathrm{HN}_{3}^{-}\) (b) \(\mathrm{N}_{2}\) (c) Azide ion (d) Nitride ion

Which of the following are Lewis acids? (i) \(\mathrm{BF}\), (ii) \(\mathrm{H}_{2} \mathrm{O}\) (iii) \(\mathrm{HSO}^{-}\)(iv) \(\mathrm{SO}_{3}\) (a) (i) and (iii) (b) (i) and (ii) (c) (i) and (iv) (d) (iii) and (iv)

Out of \(\mathrm{Ca}^{2+}, \mathrm{Al}^{3+}, \mathrm{Cr}^{3+}, \mathrm{Mg}^{2+}\), and \(\mathrm{Zn}^{2+}\), the reagents \(\mathrm{NH}_{4} \mathrm{Cl}\) and aqueous \(\mathrm{NH}_{3}\) will precipitate (a) \(\mathrm{Ca}^{2+}, \mathrm{Al}^{3+}\) (b) \(\mathrm{Al}^{3+}, \mathrm{Cr}^{3+}\) (c) \(\mathrm{Bi}^{3+}, \mathrm{Mg}^{2+}\) (d) \(\mathrm{Mg}^{2+}, \mathrm{Zn}^{2+}\)

Which among the following is the least soluble? (a) \(\mathrm{MnS}\left(\mathrm{K}_{\mathrm{sp}}=7 \times 10^{-16}\right)\) (b) \(\mathrm{FeS}\left(\mathrm{K}_{\mathrm{sp}}=4 \times 10^{-15}\right)\) (c) \(\mathrm{PtS}\left(\mathrm{K}_{\mathrm{sp}}^{4}=8 \times 10^{-73}\right)\) (d) \(\mathrm{NiS}\left(\mathrm{K}_{\mathrm{sp}}=3 \times 10^{-12}\right)\)

The dissociation constant of a substituted benzoic acid at \(25^{\circ} \mathrm{C}\) is \(1 \times 10^{-4}\). The \(\mathrm{pH}\) of a \(0.01 \mathrm{~m}\) solution of its sodium salt is (a) 6 (b) 7 (c) 8 (d) 9

Which one of the following is true for any diprotic acid, \(\mathrm{H}_{2} \mathrm{X} ?\) (a) \(\mathrm{Ka}_{2}=\mathrm{Ka}_{1}\) (b) \(\mathrm{Ka}_{2}>\mathrm{Ka}_{1}\) (c) \(\mathrm{Ka}_{1}>\mathrm{Ka}_{2}\) (d) \(\mathrm{Ka}_{2}=1 / \mathrm{Ka}_{1}\)

Which of the following statements about \(\mathrm{pH}\) and \(\mathrm{H}^{+}\) ion concentration is incorrect? (a) addition of one drop of concentrated HCl in \(\mathrm{NH}_{4} \mathrm{OH}\) solution decreases \(\mathrm{pH}\) of the solution (b) a solution of the mixture of one equivalent of each of \(\mathrm{CH}_{3} \mathrm{COOH}\) and \(\mathrm{NaOH}\) has a \(\mathrm{pH}\) of 7 (c) \(\mathrm{pH}\) of pure neutral water is not zero (d) a cold and concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4}\) has lower \(\mathrm{H}^{+}\)ion concentration than a dilute solution of \(\mathrm{H}_{2} \mathrm{SO}_{4}\)

Solubility product \(\left(\mathrm{K}_{s}\right)\) of salts \(\mathrm{mx}, \mathrm{m} \mathrm{x}_{2}\) and \(\mathrm{m} \mathrm{x}_{3}\) at T temperature are \(4 \times 10^{-8}, 3.2 \times 10^{-14}\) and \(2.7 \times 10^{-15}\) respectively. The solubilities of these salts are in the decreasing order? (a) \(\mathrm{mx}>\mathrm{mx}_{2}>\mathrm{m}_{3} \mathrm{x}\) (b) \(m_{3} x>m x_{2}>m x\) (c) \(\mathrm{mx}_{2}>\mathrm{m}_{3} \mathrm{x}>\mathrm{mx}\) (d) \(m x>m_{3} x>m x_{2}\)