JAMB Chemistry Past Questions & Answers - Page 91

451.

The compound produced when sodium peroxide is heated with excess sodium is

A.

Na2CO3

B.

Na2O

C.

NaNO2

D.

NaOH

Correct answer is B

No explanation has been provided for this answer.

452.

The radioisotope used in industrial radiography for the rapid checking of faults in welds and casting is

A.

Phosphorus-32

B.

Cobalt-60

C.

Carbon-14

D.

Iodine-131

Correct answer is B

No explanation has been provided for this answer.

453.

What is the concentration of a solution containing 2g of NaOH in 100cm3 of solution?
[Na=23, O=16, H=1]

A.

0.05 moldm-3

B.

0.30 moldm-3

C.

0.50 moldm-3

D.

0.40 moldm-3

Correct answer is C

2g NaOH is contained in 100cm3
Xg NaOH is contained in 1000cm3

Xgram = \(\frac{2\times 1000}{100}\) = 20g

Mole = \(\frac{20}{40}\) = 0.50mol/dm3

454.

The process that requires the use of hardwater in its operation is

A.

Tanning

B.

Bottling

C.

Laundry

D.

Dyeing

Correct answer is B

No explanation has been provided for this answer.

455.

Which of the following statements is true about 2-methylpropane and butane

A.

They have different number of carbon atoms

B.

They are members of same homologous series

C.

They have the same boiling points

D.

They have different chemical properties

E.

They are members of same homologous series and Isomers as well

Correct answer is B

No explanation has been provided for this answer.