Question 466:

• JAMB 1986

A substance Z reacts with NaOH to give salt and water only. When Z is treated with dilute HCl, a gas is evolved which gives a yellow suspension on passing into concentrated H₂SO₄. Substance Z is?

A. NaHS
B. Na₂SO₃
C. Na₂S
D. NaHSO₃

Question 467:

• JAMB 1986

Ammonia gas is normally dried with?

A. Concentrated sulphuric acid
B. Quicklime
C. Anhydrous calcium chloride
D. Magnesium sulphate

Question 468:

• JAMB 1986

What are the values of x, y and z respectively in the equation: xCu + yHNO₃ → xCu(NO₃)₂ + 4H₂O + zNO?

A. 4: 1: 2
B. 3:8:2
C. 2:8:3
D. 8:3:2

Question 469:

• JAMB 1986

The iron (III) oxide impurity in bauxite can be removed by?

A. Fractional crystallization in acid solution
B. Dissolution in sodium hydroxide and filtration
C. Extraction with concentrated ammonia and reprecipitation
D. Electroysis of molten mixture

Question 470:

• JAMB 1986

Which of the following does NOT contain aluminium as component?

A. Over-head cables
B. Duralumin
C. Container for caustic soda
D. Container for nitric acid