JAMB Chemistry Past Questions & Answers - Page 109

541.

What volume of 0.5mldm3 H2SO4 will exactly neutralize 20cm3 of 0.1moldm3 NaOH Solution?

A.

2.0cm3

B.

5.0cm3

C.

6.8cm3

D.

8.3cm3

Correct answer is A

2NaOH + H2SO4 → Na2SO4 + 2H2O
CaVa) ÷ (CbVb) = ratio of acid / ratio of base
0.5Va ÷ (0.1 × 20) = ½
Va = 2.0cm3

542.

Which of the following types of alkanols undergo oxidation to produce alkanoic acids.

I. Primary alkanols
II. Secondary alkanols
III. Tertiary alkanols

A.

I, II and III

B.

I and II only

C.

III only

D.

I only

Correct answer is D

Only primary alkanols undergo oxidation to produce alkanoic acid. Option A,B,C will not produce alkanoic acid

543.

Hydrogen can be displaced from a hot alkaline solution by

A.

Fe

B.

Cu

C.

Ca

D.

Sn

Correct answer is D

Tin dissolves in concentrated solution of alkalis to give trioxostannate(IV) salt and hydrogen.

544.

A fixed mass of gas occupies 92cm3 at 3°C. What will be its volume at 18C if the pressure remains constant?

A.

15.3cm3

B.

87.3cm3

C.

2.0cm3

D.

97.0cm3

Correct answer is D

\(\frac{V_{1}}{T_{1}}\) = \(\frac{V_{2}}{T_{2}}\)
\(T_{1}\) = 3 + 273 = 276K
\(T_{2}\) = 18 + 273 = 291K
\(V_{1}\) = \(92cm^{3}\)
\(V_{2}\) = ?
\(V_{2}\) = \(\frac{V_{1}T_{2}}{T_{1}}\)

=\(\frac{92 \times 291}{276}\) 
= \(97.0cm^{3}\)

545.

Tartaric acid is used industrially to

A.

make baking powder

B.

make fruit juice

C.

remove rust

D.

dry substance

Correct answer is A

A is the correct answer. Tartaric acid is found in cream of tartar, which is used in cooking candies and frostings for cakes. Tartaric acid is also found in baking powder, where it serves as the source of acid that reacts with sodium bicarbonate (baking soda)