Question

Question. All elements of Group 15 show allotropy except:(a)Nitrogen(b)Arsenic(c)Antimony(d)Bismuth Answer: (a)Nitrogen (due to small size and high electronegativity N-N is weak)

Question. Solubility of gases in liquids decreases with rise in temperature because dissolution is an:(a)endothermic and reversible process(b)exothermic and reversible process(c)endothermic and irreversible process(d) exothermic and irreversible process Answer: (b)exothermic and reversible process (according to Le -Chatlier principle Solubility of gases in liquids decreases with rise in temperature)

Q. Covalency of nitrogen is restricted to:(a)2(b)3(c)4(d)5 Answer: (c)4 (Covalency of nitrogen is restricted to 4 due to non availability of d orbitals)

Q. Which of the following is a correct statement for C2H5Br?(a) It reacts with metallic Na to give ethane.(b) It gives nitroethane on heating with aqueous solution of AgNO2(c) It gives C2H5OH on boiling with alcoholic potash.(d) It forms diethylthioether on heating with alcoholic KSH. Answer: (b) It gives nitroethane on heating with aqueous solution

Q. Major product obtained on reaction of 3-Phenyl propene with HBr in presence of organic peroxide(a)3- Phenyl 1- bromopropane(b) 1 –Phenyl -3- bromopropane(c) 1-Phenyl -2-bromopropane(d) 3-Phenyl -2- bromopropane Answer: (b) 1 –Phenyl -3- bromopropane ((C6H5)CH2CH=CH2 + HBr (organic peroxide) => (C6H5)CH2CH2CH2Br anti-Markovnikov addition)

Q. Which of the following statement is correct:(a)Fibrous proteins are generally soluble in water(b)Albumin is an example of fibrous proteins(c)In fibrous proteins, the structure is stabilised by hydrogen bonds and disulphide bonds(d)pH does not affect the primary structure of protein. Answer: (d)pH does not affect the primary structure of protein (pH effects the tertiary structure)

Q. Which of the following has the lowest boiling point:(a)H2O(b)H2S(c)H2Se(d)H2Te Answer: (b)H2SH2S (boiling point increases down the group but water forms strong hydrogen bonds sohas higher boiling point than H2S)

Q. The boiling points of alcohols are higher than those of hydrocarbons of comparable masses due to:(a) Hydrogen bonding( b) Ion – dipole interaction(c) Dipole- dipole interaction(d) Van der Waal’s forces. Answer: (a) Hydrogen bonding (alcohols form intermolecular hydrogen bonds)

Q. Which of the following is an example of a solid solution?(a)sea water(b)sugar solution(c)smoke(d)22 carat gold Answer: (d)22 carat gold (it is an alloy so solid in solid solution)

Q. Which of the following reactions is used to prepare salicylaldehyde?(a) Kolbe’s reaction(b) Etard reaction(c) Reimer- Tiemann reaction(d) Stephen’s reduction. Answer: (c) Reimer- Tiemann reaction (c) Reimer- Tiemann reaction ( Kolbe’s reaction is used to prepare salicylic acid, Etard reaction for benzaldehyde, Reimer- Tiemann reaction for salicylaldehyde and Stephen’s reduction for aldehyde)