What product is formed at the cathode during the electrolysis of concentrated sodium chloride solution using carbon electrodes?

• A. Chlorine
• B. Hydrogen
• C. Oxygen
• D. Sodium

A mixture of iodine and sulphur crystals can be separated by treatment with?

• A. Water to filter off sulphur
• B. carbon (IV) sulphide to filter off iodine
• C. ethanoic acid to filter off sulphur
• D. methanol to filter off iodine

Soaps clean surfaces on the principle based on?

• A. viscosity
• B. floatation
• C. elasticity
• D. surface tension

(a) In an experiment, 25.0 cm\(^{3}\) of H\(_{2}\)SO\(_{4}\) completely neutralized 24.0 cm\(^{3}\) of a 0.1 50 mol dm\(^{-3}\) aqueous KOH using a suitable indicator.

(i) Write a balanced chemical equation for the reaction.

(ii) Calculate the concentration of the acid solution.

(b)i. A burning magnesium ribbon was placed in a gas jar containing Carbon (IV) oxide.

- Write an equation for the reaction.

- Explain briefly why the magnesium ribbon burns in carbon(lV) oxide although the gas does not support combustion.

- Calculate the percentage mass of nitrogen in magnesium trioxonitrate (V). |N = 140. O = 16.0. Mg = 24.01]

(c) Consider the following organic compound: CH\(_{3}\)CH\(_{2}\)CH = CHCOOH.

(i) State two chemical reactions which could he sed te identify the compound.

(ii) What would be observed in each of the reactions stated in c(i)

(d) Describe briefly how soap is manufactured using pellets of sodium hydroxide and vegetable oil

(e) Define the term electronegativity

A carcinogenic substance is

• A. asbestos dust
• B. sawdust
• C. nitrogen (II) oxide
• D. carbon (II) oxide

Which one of the following is a brittle material?

• A) rubber
• B) plastic
• C) thermoplastic
• D) glass

The major and most effective way of controlling pollution is to

• A) improve machinery so that the substances released from combustion are less harmful
• B) pass strict laws against it by individuals and companies
• C) educate people on the causes and effects of pollution
• D) convert chemical wastes to harmless substances before releasing them into the environment

A colourless and odourless gas X burns in oxygen with a pale blue flame.

(a) Suggest two gases which X could be.

(b) Give one chemical test that could be used to confirm which of the two gases X is.

The component of an atom that contributes least to its mass is the

• A. proton
• B. nucleus
• C. neutron
• D. electron

The process by which alkanoic acid reacts reversibly with alkanols is known as?

• A. saponification
• B. esterification
• C. carboxylation
• D. halogenation