Polytechnic Chemistry Set 15

281. The allotrope of carbon that has a high melting point is

Graphite Fullerene Coke Diamond

Answer: Diamond

282. The compound that gives a smoky flame when burned is

CH₄ C₂H₆ C₂H₂ C₂H₄

Answer: C₂H₂

283. The process of adding hydrogen to an alkene in the presence of a nickel catalyst is called _______.

Hydrogenation Dehydrogenation Addition and elimination Substitution

Answer: Hydrogenation

284. A compound ‘A’ with the formula C₃H₆O has two structural isomers. Upon hydrogenation, it forms an acid. The compound A is

1-Propanal 2-Propanone 1-Propanol 2-Propanol

Answer: 2-Propanone

285. The toxic organic compound present in denatured spirit is

Ethyl alcohol Methyl alcohol Acetic acid Formic acid

Answer: Methyl alcohol

286. The hydrolytic cleavage of an ester in the presence of alkali is called

Esterification Saponification Substitution Addition

Answer: Saponification

287. Vegetable oils generally contain

Unsaturated fatty acids Carboxylic acids Saturated fatty acids Glacial acetic acid

Answer: Unsaturated fatty acids

288. Heavy water forms foam with soap; this is due to _______.

CH₃COOH NaOH Ca(OH)₂ CaCl₂

Answer: NaOH

289. The hydrophobic end of a micelle is soluble in hydrocarbons because it is

Non-polar Polar Ionic Co-ordinate

Answer: Non-polar

290. Compounds that do not belong to the homologous series are

CH₄O C₄H₁₀O C₂H₆O C₃H₈O

Answer: CH₄O

291. The process of forming long chains by bonding with other atoms is called

Addition Coordination Chain formation Polymerization

Answer: Polymerization

292. CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O; X is

H₂SO₄ NaOH KMnO₄ Ni

Answer: H₂SO₄

293. The modern periodic law is based on

Atomic mass Mass number Atomic number Electronic configuration

Answer: Atomic number

294. In Mendeleev’s periodic table, the elements with atomic numbers 18 and 35 belong to which group?

Group I Group III Group V Group VII

Answer: Group VII

295. The element whose nature is electropositive is

Sulfur Silicon Boron Copper

Answer: Copper

296. The second most electronegative element in the periodic table is

Fluorine Chlorine Oxygen Nitrogen

Answer: Chlorine

297. The element with half-filled outermost electronic configuration is

Aluminum Magnesium Boron Nitrogen

Answer: Nitrogen

298. The order of effective nuclear charge is

Li < Na < K < Rb Li > Na > K > Rb Li < K < Na < Rb Li < Rb < K < Na

Answer: Li > Na > K > Rb

299. Which of the following is a triad?

H, F, Cl F, Cl, Br Be, Mg, Ca Ca, Sr, Ba

Answer: F, Cl, Br

300. KOH is a stronger base than LiOH; the reason is

Li is highly reactive Li has a smaller atomic size K is highly reactive K has a larger atomic size

Answer: K has a larger atomic size