Chapter 16

\(\mathrm{BCl}_{3}\) is a planar molecule because in this molecule boron is (a) sp \(^{2}\)-hybridized (b) sp-hybridized (c) sp \(^{3}\)-hybridized (d) sp^{3} d - h y b r i d i z e d ~

In diborane (a) 2-bridged hydrogens and four terminal hydrogens are present (b) 3-bridged hydrogens and three terminal hydrogens are present (c) 4-bridged hydrogens and two terminal hydrogens are present (d) none of the above

Which one of the following boron compounds is optically active? (a) boron anhydride (b) sodium tetraborate (c) borosalicylic acid (d) boron trifluoride

Borax is not used (a) as a flux in soldering (b) in making enamel and pottery glazes (c) as a styptic to stop bleeding (d) in making optical glasses

Which of the following compounds are formed when \(\mathrm{BCl}_{3}\) is treated with water? (a) \(\mathrm{B}_{2} \mathrm{O}_{3}+\mathrm{HCl}\) (b) \(\mathrm{H}_{3} \mathrm{BO}_{3}+\mathrm{HCl}\) (c) \(\mathrm{B}_{2} \mathrm{H}_{6}+\mathrm{HCl}\) (d) none of these

Which of the following is the strongest Lewis acid? (a) \(\mathrm{BBr}_{3}\) (b) \(\mathrm{BCl}_{3}\) (c) \(\mathrm{BI}_{3}\) (d) \(\mathrm{BF}_{3}\)

Which of the following reacts with \(\mathrm{BCl}_{3}\) to form diborane? (a) \(\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\) (b) \(\mathrm{NH}_{3}\) (c) \(\mathrm{NaHg}\) (d) \(\mathrm{LiAlH}_{4}\)

In the reaction \(\mathrm{B}_{2} \mathrm{H}_{6}+2 \mathrm{KOH}+2 \mathrm{X} \longrightarrow 2 \mathrm{Y}+6 \mathrm{H}_{2}\) \(\mathrm{X}\) and \(\mathrm{Y}\) are respectively (a) \(\mathrm{HCl}, \mathrm{KBO}_{3}\) (b) \(\mathrm{H}_{2}, \mathrm{H}_{3} \mathrm{BO}_{3}\) (c) \(\mathrm{H}_{2} \mathrm{O}, \mathrm{KBO}_{2}\) (d) \(\mathrm{H}_{2} \mathrm{O}, \mathrm{KBO}_{3}\)

Reactivity of borazole is greater than that of benzene because (a) it has localized electron in it (b) borazole is electron deficient compound (c) borazole is polar compound (d) borazole is non-polar compound

In diborane, the two \(\mathrm{H}-\mathrm{B}-\mathrm{H}\) angles are nearly (a) \(60^{\circ}, 120^{\circ}\) (b) \(95^{\circ}, 150^{\circ}\) (c) \(95^{\circ}, 120^{\circ}\) (d) \(120^{\circ}, 180^{\circ}\)

\(\mathrm{H}_{3} \mathrm{BO}_{3}\) is (a) monobasic and a weak lewis acid (b) monobasic and a weak bronsted acid (c) monobasic and a strong lewis acid (d) tribasic and a weak bronsted acid

Mark the wrong statement which of the following statements about/regarding \(\mathrm{BF}_{3}\) is incorrect? (a) it forms an addition compound with \(\mathrm{NH}_{3}\) (b) it is a volatile liquid at room temperature (c) it combines with either to form boron trifluoride etherate (d) it acts as a Lewis acid

Boron when heated with carbon forms (a) \(\mathrm{B}_{4} \mathrm{C}\) (b) \(\mathrm{B}_{2} \mathrm{C}_{3}\) (c) \(\mathrm{BC}_{2}\) (d) \(\mathrm{B}_{4} \mathrm{C}_{3}\)

When strongly heated, orthoboric acid gives (a) \(\mathrm{H}_{2} \mathrm{~B}_{4} \mathrm{O}_{7}\) (b) \(\mathrm{B}_{2} \mathrm{O}_{3}\) (c) \(\mathrm{HBO}_{2}^{+}\) (d) \(\mathrm{NaBO}_{2}+\mathrm{B}_{2} \mathrm{O}_{3}\)

From \(\mathrm{B}_{2} \mathrm{H}_{6}\), all the following can be prepared except (a) \(\mathrm{B}_{2}\left(\mathrm{CH}_{3}\right)_{6}\) (b) \(\mathrm{NaBH}_{4}\) (c) \(\mathrm{B}_{2} \mathrm{O}_{3}\) (d) \(\mathrm{H}_{3} \mathrm{BO}_{3}\)

Which of the following is the chemically inactive, allotropic form of carbon? (a) coal (b) diamond (c) animal charcoal (d) charcoal

The use of diamond as a gem depends on its (a) chemical inertness (b) hardness (c) purest form of carbon (d) high refractive index

Moderate electrical conductivity is shown by (a) diamond (b) carborundum (c) graphite (d) silica

If \(\mathrm{CO}\), is passed in excess through lime water, the milkiness first formed disappears due to (a) formation of water soluble calcium bicarbonate (b) the solution getting heated by exothermic reaction (c) reversal of the original reaction (d) formation of volatile calcium derivative

When \(\mathrm{SiO}_{2}\) is reacted with sodium carbonate, which gas is liberated? (a) \(\mathrm{O}_{2}\) (c) \(\mathrm{CO}^{2}\) (b) \(\mathrm{O}_{3}\) (d) \(\mathrm{CO}_{2}^{3}\)

Silica is soluble in (a) HF (b) \(\mathrm{HNO}_{3}\) (c) \(\mathrm{H}_{2} \mathrm{SO}_{4}\) (d) \(\mathrm{HCl}\)

One can obtain a silica garden if (a) silicon salts are grown in garden (b) crystals of coloured cations are added to a strong solution of sodium silicate (c) silicon tetrafluoride is hydrolyzed (d) sodium silicate solution is heated with a base

\((\mathrm{Me})_{2} \mathrm{SiCl}_{2}\) on hydrolysis will produce (a) \((\mathrm{Me})_{2} \mathrm{Si}(\mathrm{OH})_{2}\) (b) \((\mathrm{Me})_{2}^{2} \mathrm{Si}=\mathrm{O}\) (c) \(-\left[-\mathrm{O}-(\mathrm{Me})_{2} \mathrm{SI}-\mathrm{O}-\right]_{\mathrm{a}}-\) (d) \(\mathrm{Me}_{2} \mathrm{SiCl}(\mathrm{OH})\)

What is the molecular formula of white phosphorus? (a) \(\mathrm{P}_{2}\) (c) \(\mathrm{P}_{3}\) (b) \(\mathrm{P}_{4}\) (d) \(\mathrm{P}_{16}\)

Which of the following is an acid? (a) \(\mathrm{P}(\mathrm{OH})_{3}\) (b) \(\mathrm{NaOH}\) (c) \(\mathrm{NH}_{4} \mathrm{OH}\) (d) \(\mathrm{Ca}(\mathrm{OH})_{2}\)

In the reaction \(\mathrm{P}_{4}+3 \mathrm{KOH}+3 \mathrm{H}_{2} \mathrm{O} \longrightarrow \mathrm{PH}_{3}+3 \mathrm{KH}_{2} \mathrm{PO}_{2}\) phos- phorus is (a) oxidized (b) reduced (c) oxidized and reduced (d) neither oxidized nor reduced

The reduction of calcined phosphate rock with coke and sand in an electric arc furnace at \(1773 \mathrm{~K}\) gives a number of products including (a) silicon (b) calcium hydride (c) phosphorus (d) calcium oxide

'Nitrolim' is a mixture of (a) \(\mathrm{CaCN}_{2}\) and \(\mathrm{N}_{2}\) (b) \(\mathrm{CaCN}_{2}\) and graphite (c) \(\mathrm{CaC}_{2}\) and graphite (d) \(\mathrm{Ca}(\overline{C N})_{2}\) and graphite

Which allotrope of phosphorus is thermodynamically most stable? (a) red (b) black (c) white (d) yellow

One mole of calcium phosphide on reaction with excess water gives (a) one mole of phosphine (b) two moles of phosphoric acid (c) two moles of phosphine (d) one mole of phosphorus pentroxide

Each of the following is true for white and red phosphorus except that they (a) can be oxidized by heating in air (b) can be converted into one another (c) are both soluble in \(\mathrm{CS}_{2}\) (d) consist of the same kind of atoms

Which one of the following substances is used as a fertilizer? (a) \(\mathrm{Ca}(\mathrm{CN})_{2}\) (b) \(\mathrm{CaSO}_{4}\) (c) \(\mathrm{K}_{2} \mathrm{SO}_{4} \cdot \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3} .14 \mathrm{H}_{2} \mathrm{O}\) (d) \(\mathrm{Ca}\left(\mathrm{H}_{2} \mathrm{PO}_{4}\right)_{2} \mathrm{H}_{2} \mathrm{O} \cdot 2\left(\mathrm{CaS} \mathrm{O}_{4} \cdot 2 \mathrm{H}_{2} \mathrm{O}\right)\)

\(\mathrm{P}_{2} \mathrm{O}_{5}\) is heated with water to give (a) hypophosphoric acid (b) orthophosphoric acid (c) hypophosphorus acid (d) phosphorus acid

Basicity of orthophosphoric acid is (a) 5 (b) 4 (c) 3 (d) 2

\(\mathrm{H}_{3} \mathrm{PO}_{2}\) is the molecular formula of an acid of phosphorus. Its name and basicity respectively are (a) hypophosphoric acid and two (b) hypophosphorus acid and one (c) hypophosphorus acid and two (d) phosphorus acid and two

The structural formula of hypophosphorus acid

Repeated use of which one of the following fertilizers would increase the acidity of the soil? (a) ammonium sulphate (b) potassium nitrate (c) urea (d) superphosphate of lime

Which of the following statements is not true about ammonia? (a) It is the most basic hydride in its group (b) It can have hydrogen bonding (c) It has less dipole moment than \(\mathrm{NF}_{3}\) (d) It has 3 bp and 1 lp electron pairs.

For \(\mathrm{H}_{3} \mathrm{PO}_{3}\) and \(\mathrm{H}_{3} \mathrm{PO}_{4}\), the correct choice is: (a) \(\mathrm{H}_{3} \mathrm{PO}_{3}\) is dibasic and reducing (b) \(\mathrm{H}_{3} \mathrm{PO}_{3}\) is dibasic and non-reducing (c) \(\mathrm{H}_{3}^{3} \mathrm{PO}_{A}^{3}\) is tribasic and reducing (d) \(\mathrm{H}_{3} \mathrm{PO}_{4}\) is tribasic and non-reducing

The number of \(\mathrm{P}-\mathrm{O}-\mathrm{P}\) bonds in cyclic metaphosphoric acid is (a) \(\mathrm{zer} \mathrm{O}\) (b) two (c) three (d) four

Sulphur trioxide is dissolved in heavy water to form a compound \(\mathrm{X}\). The hybridization state of sulphur in \(\mathrm{X}\) is (a) sp (b) \(\mathrm{sp}^{2}\) (c) \(s p^{3}\) (d) \(\mathrm{dsp}^{2}\)

Which compound acts as an oxidizing as well as a reducing agent? (a) \(\mathrm{SO}\) (b) \(\mathrm{MnO}_{2}\) (c) \(\mathrm{Al}_{2} \mathrm{O}_{3}\) (d) \(\mathrm{CrO}_{3}\)

\(\mathrm{SO}_{2}\) behaves as a reducing agent when (a) passed through \(\mathrm{FeSO}_{4}\) solution (b) passed over hot \(\mathrm{CuO}\) (c) mixed with moist \(\mathrm{H}_{2} \mathrm{~S}\) (d) passed through acidified \(\mathrm{KMnO}_{4}\) solution

When an article is bleached by \(\mathrm{SO}_{2}\) it loses its colour. The colour can be restored by (a) heating (b) exposure to air (c) dilution (d) none of these

Which catalyst is used in the manufacture of sulphuric acid by Contact Process? (a) Ni powder (b) Platinized asbestos (c) anhydrous \(\mathrm{Al}_{2} \mathrm{O}_{3}\) (d) Al powder

The product obtained at anode when a \(50 \%\) aqueous solution of \(\mathrm{H}_{2} \mathrm{SO}_{4}\) is electrolyzed using platinum electrodes is (a) \(\mathrm{H}_{2}\) (b) \(\mathrm{O}\), (c) \(\mathrm{H}_{2} \mathrm{SO}_{3}\) (d) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{\mathrm{g}}\)

Sodium thiosulphate is prepared by (a) reducing \(\mathrm{Na}_{2} \mathrm{SO}_{4}\) solution with \(\mathrm{H}_{2} \mathrm{~S}\) (b) boiling \(\mathrm{Na}_{2} \mathrm{SO}_{3}\) solution with \(\mathrm{S}\) in alkaline medium (c) neutralizing \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\) solution with \(\mathrm{NaOH}\) (d) boiling \(\mathrm{Na}_{2} \mathrm{SO}_{3}\) solution with \(\mathrm{S}\) in acidic medium

A bottle completely filled with conc. \(\mathrm{H}_{2} \mathrm{SO}_{4}\) is left unstoppered for several days and we observe spontaneous overflow of acid. It is due to (a) dehydration of \(\mathrm{H}_{2} \mathrm{SO}_{4}\) (b) absorption of air by \(\mathrm{H}_{2} \mathrm{SO}_{4}\) (c) hygroscopic nature of \(\mathrm{H}_{2} \mathrm{SO}_{4}\) (d) change in temperature

In \(\mathrm{SO}_{3}^{2}\) (a) there is sp \(^{3}\) hybridized sulphur atom (b) bonds between \(\mathrm{S}\) and \(\mathrm{O}\) are equivalents (c) d \(\pi-\mathrm{p} \pi\) bond between \(\mathrm{S}\) and \(\mathrm{O}\) is delocalized (d) all the facts given here are true

Which of the following sequence is correct with reference to the oxidation number of iodine? (a) \(\mathrm{HI}<\mathrm{I}_{2}<\mathrm{ICl}<\mathrm{HIO}_{4}\) (b) \(\mathrm{I}_{2}<\mathrm{HI}<\mathrm{ICl}<\mathrm{HIO}_{4}\) (c) \(\mathrm{HIO}_{4}<\mathrm{ICl}<\mathrm{I}_{2}<\mathrm{HI}\) (d) \(\mathrm{I}_{2}<\mathrm{ICl}<\mathrm{HI}<\mathrm{HIO}_{4}\)