JAMB Past Questions and Answers - Page 1527

7,631.

The balanced equation for the reaction of tetraoxosulphate(VI)acid with aluminium hydroxide to give water and aluminium tetraoxosulphate(VI) is

A.

H2SO4 + Al(OH)2 \(\to\) 2H2O + AlSO4

B.

3H2SO4 + 2Al(OH)3 \(\to\) 6H2O + Al2(SO4)3

C.

3H2SO4 + 2AlH \(\to\) 6H2O + Al(SO4)3

D.

3H2 SO4 + 2Al(OH)3 \(\to\) Al(SO4)3

E.

H2SO4 + Al(OH)3 \(\to\) H2O + Al2(SO4)3

Correct answer is B

No explanation has been provided for this answer.

7,632.

The ratio of the number of molecules in 2g of hydrogen to that in 16g of oxygen is

A.

2:1

B.

1:1

C.

1:2

D.

1:4

E.

1:8

Correct answer is A

No explanation has been provided for this answer.

7,633.

Naphthalene when heated melts at 354 K (81 oC). At this temperature the molecules of naphthalene

A.

decompose into smaller molecules

B.

change their shape

C.

are oxidized by atmospheric oxygen

D.

contract

E.

become mobile as the inter molecular forces are broken

Correct answer is E

No explanation has been provided for this answer.

7,634.

Which among the elements 1. Carbon 2. Oxygen 3. Copper 4. Bromine 5. Zinc, will NOT react with either water or steam?

A.

1 and 2

B.

2 and 3

C.

3 and 4

D.

1, 2, and 3

E.

2, 3, and 5

Correct answer is B

No explanation has been provided for this answer.

7,635.

A molar solution of caustic soda is prepared by dissolving

A.

40 g NaOH in 100 g of water

B.

40 g NaOH in 1000 g of water

C.

20 g NaOH in 500 of solution

D.

20 g NaOH in 1000 g of solution

E.

20 g NaOH in 80 g of solution

Correct answer is B

A molar solution implies concentration in terms of moles/liter. The respective atomic weights for NaOH are: Na - 23,0 - 16 and H - 1, so the molecular weight, is 23 + 16 + I = 40. Thus 40 grams of NaOH equals one mole of NaOH, and a 1 molar solution of NaOH will contain 40 grams of NaOH chemical in 1000grams of water.