Chemistry Past Questions and Answers

What process is illustrated below? S_(s) â‡Œ^H₂Oâ‡Œ S _(aq)

A Decomposition of a solid
B Melting of a solid
C Formation of saturated solution of a solid
D Sublimation of a solid

Question 892:

A solution of a salt X reacts with AgNO₃ solution to give white precipitate which dissolves in excess aqueous ammonia. X contains

A CI^-
B Pb ²⁺
C SO ^2-
D Zn²⁺

Question 893:

Consider the reaction represented by the following equation: N_2(g) + 3H_2(g) â‡Œ 2NH_3(g); âˆ†H = - 92kJmol¹. Finely divided iron is used as catalyst in the reaction in order to

A Lower the value of âˆ†H
B Increase the time for attainment of equilibrium
C Shorten the time for attainment of equilibrium
D Decrease the yield of ammonia

Question 894:

Which of these cell notations is the correct representation of a Daniell cell?

A Zn_(s) / Zn²⁺_{(aq) // Cu²⁺^(aq)/Cu[sub](s)}[/sub]
B Cu_(s) / CU^{2+_(aq) // Zn[sup]2+}_(aq) / Zn_(s)[/sup]
C Zn²⁺_(aq) / Zn_(s) // Cu²⁺_(aq) /Cu_(s)
D Cu²⁺_(aq) / Cu_(s) // Zn_(s) / Zn²⁺_(aq)

Question 895:

What is the oxidation number of chromium in K₂CrO₄?

A +1
B +2
C +4
D +6