Chemistry Past Questions and Answers

How many Faraday of electricity are required to deposit 0.20 mole of nickel, if 0.10 Faraday of electricity deposited 2.98g of nickel during electrolysis of its aqueous solution?
(Ni = 58.7, 1F = 96 500 C mol^-)

A 0.20
B 0.30
C 0.40
D 0.50

Question 22:

What is the oxidation number of Z in K₃ZCl₆?

A -3
B +3
C -6
D +6

Question 23:

2H₂S_(g) + SO_2(g) + H₂O_(I) â†’ 3S_(s) + 3H₂O_(I)..........(i) 3CuO_(s) + 2NH_3(g) â†’ 3Cu_(s) + 3H₂O_(I) + N_2(g).........(II) In the equations above, the oxidizing agent (I) and the reducing agent in (II) respectively are?

A H₂S_{and NH[sub]3}[/sub]
B SO₂ and CuO
C SO₂ and NH₃
D H₂S_{and CuO}

Question 24:

2SO_2(g) + O_2(g) 2SO₃. In the reaction above, the standard heats of formation of SO_2(g) and SO_3(g) are -297 KJ mol^-1 respectively. The heat change of the reaction is?

A -99 kJ mol^-
B -198 kJ mol^-
C +198 kJ mol^-
D +683kJ mol^-

Question 25:

If the rate law obtained for a given reaction is rate = k(X)ⁿ (Y)^m, what is the overall order of the reaction?

A Nm
B N/m
C N + m
D N - m