CIE Chemistry (US-0439): Specimen Questions with Answers 205 - 207 of 240

Question number: 205

Short Answer Question▾

Write in Short

Suggest why a solution of malonic acid, concentration 0.2 mol/dm3, has a higher pH than one of sulfuric acid of the same concentration.

[1 Marks]

Explanation

Because the sulfuric acid have low melting point and malonic has high melting point than malonic acid.

Question number: 206

MCQ▾

Question

Which of the statements about ethanol are correct?

1 Ethanol can be formed by an addition reaction.

2 Ethanol can be formed by fermentation.

3 When ethanol burns in air, it forms carbon dioxide and water.

Choices

Choice (4) Response

a.

b.

c.

d.

Answer

a.

Explanation

Correct option is A means all because Ethanol can be made by reacting ethene (from cracking crude oil fractions) with steam. The combustion of ethanol is an exothermic reaction so it forms , and heat. Ethanol can also be formed by fermentation of glucose

Question number: 207

Short Answer Question▾

Write in Short

Water reacts with sodium. The products are sodium hydroxide and hydrogen. Write a word equation for this reaction

Explanation

Sodium metal reacts rapidly with water to form a colourless solution of sodium hydroxide and hydrogen gas . The reaction is exothermic. The reaction is given below.

 Image Exothermic A

Image Exothermic A

Image Exothermic A

 Image Exothermic D

Image Exothermic D

Image Exothermic D

 Image Exothermic C

Image Exothermic C

Image Exothermic C

 Image Exothermic B

Image Exothermic B

Image Exothermic B