Generally, the first ionization energy increases along a period. But there are some exceptions. One which is NOT an exception is Na and Mg

211.    Generally, the first ionization energy increases along a period. But there are some exceptions. One which is NOT an exception is ______.

(A) Na and Mg

(B) N and O

(C) Be and B

(D) Mg and Al

Answer:: (A)

212.    Which one of these is NOT true for benzene?

(A) There are three carbon-carbon single bonds and three carbon-carbon double bonds.

(B) It forms only one type of monosubstituted product.

(C) The bond angle between the carbon-carbon bonds is 1200.

(D) The heat of hydrogenation of benzene is less than the theoretical value.

Answer:: (A)

213.    Gram molecular volume of oxygen at STP is

(A) 11200 cm3

(B) 22400 cm3

(C) 5600 cm3

(D) 3200 cm3

Answer:: (B)

214.    Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behaviour is that graphite

(A) has molecules of variable molecular masses like polymers.

(B) has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds.

(C) is a non-crystalline substance.

(D) is an allotropic form of carbon.

Answer:: (B)

215.    Helium is used in balloons in place of hydrogen because it is

(A) incombustible

(B) lighter than hydrogen

(C) radioactive

(D) more abundant than hydrogen

Answer:: (A)

216.    Hofmann's bromamide reaction is to convert

(A) amine to amide

(B) amide to amine

(C) alcohol to acid

(D) acid to alcohol

Answer:: (B)

217.    How many chiral carbon atoms are present in 2, 3, 4 - trichloropentane?

(A) 3

(B) 2

(C) 1

(D) 4

Answer:: (B)

218.    How many optically active stereomers are possible for butan-2, 3-diol?

(A) 1

(B) 2

(C) 3

(D) 4

Answer:: (B)