Question 631:

• JAMB 1990

Iron galvanized with zinc is cathodically protected from corrosion. This is because?

A. Zinc has a more positive oxidation potential than iron
B. Zinc has less positive oxidation potential than iron
C. Bith have the same oxidation potential
D. Zinc is harder than iron

Question 632:

• JAMB 1990

Which of the following samples will react fastest with dilute trioxonitrate (V) acid?

A. 5 g of lumps of CacO₃ at 25°C
B. 5 g of powered CacO₃ at 25°
C. 5 g of lumps of CaCO₃ at 50°C
D. 5 g of powered CaCO₃ AT 50°C

Question 633:

• JAMB 1990

In the reaction:
2Hl_(g) ↔ H_2(g) + l_2(g)' ΔH = 10 kj;
The concentration of iodine in the equilibrium mixture can be increased by?

A. Raising the pressure
B. Raising the temperature
C. Adding a catalyst
D. Lowering the pressure

Question 634:

• JAMB 1990

Which of the following gases can be collected by the upward displacement of air?

A. NO
B. H ₂
C. NH₃
D. Cl ₂

Question 635:

• JAMB 1990

The brown fumes given off when trioxonitrate (V) acid is heated consist of ?

A. NO₂ and O₂
B. H₂O and NO₂
C. NO_2' O₂ and H₂O
D. NO, NO₂ and H₂O