NECO Chemistry Past Questions & Answers - Page 29

142.

The best way to distinguish between Na2CO3and NaHCO2 is by.

A.

adding an acid.

B.

adding an alkali.

C.

dissolving in water.

D.

exposing to air.

E.

heating

Correct answer is E

No explanation has been provided for this answer.

143.

The Kinetic theory can NOT be used to explain

A.

allotropy

B.

Brownian movement.

C.

diffusion

D.

Tyndal effect.

E.

vaporization

Correct answer is A

No explanation has been provided for this answer.

144.

The molar mass of a compound X is 56. its empirical formula is CH2. X is

A.

butene

B.

butyne

C.

ethene

D.

propene

E.

propyne

Correct answer is A

\((CH_{2})x = 56\)

\((12 + 2)x = 56\)

\(14x = 56\)

\(x = \frac{56}{14}\)

\(x = 4\)

Hence, the empirical formula is \((CH_{2}) \times 4\) 

= \(C_{4}H_{8}\)

145.

Which compound will have the lowest boiling point?

A.

CH3OH

B.

CH3COOH

C.

CH3CHOH

D.

C4H10

E.

(CH3)3CH

Correct answer is D

No explanation has been provided for this answer.