Identify the substance underlined in each of the following:

(i) The electrode that increases in mass during the electro-refining of silver.

(ii) The acid that is a dehydrating as well as a drying agent.

(iii) The catalyst used to oxidize ammonia into nitric oxide.

Copy and complete the following paragraph using the options given in brackets:

Alkenes are a homologous series of (i) …………… [saturated/unsaturated] hydrocarbons characterized by the general formula (ii) …………… [C_nH_2n+2/C_nH_2n]. Alkenes undergo (iii) …………… [addition/substitution] reactions and also undergo (iv) …………… [hydrogentaion/dehydrogenation] to form alkanes.

Write balanced chemical equations, for the preparation of given salts (i) to (iii) by using the methods A to C respectively.

A: Neutralization
B: Precipitation
C: Titration

(i) Copper sulphate
(ii) Zinc carbonate
(iii) Ammonium sulphate

An aqueous solution of nickle [II] sulphate was electrolyzed using nickle electrodes. Observe the diagram and answer the questions that follow:

(i) What do you observe at the cathode and anode respectively.

(ii) Name the cation that remains as a spectator ion in the solution.

(iii) Which equation for the reaction at the anode is correct.

1. Ni ⟶ Ni²⁺ + 2e^-
2. Ni + 2e^- ⟶ Ni²⁺
3. Ni²⁺ ⟶ Ni + 2e^-
4. Ni²⁺ + 2e^- ⟶ Ni