CIE Chemistry (US-0439): Specimen Questions with Answers 24 - 26 of 240

Question number: 24

MCQ▾

Question

Two indicators, bromophenol blue and Congo red, show the following colors in acidic solutions and in alkaline solutions.

Table of Two indicators

Table of Two Indicators

Table of Two indicators

A few drops of each indicator are added to separate samples of a solution of pH 2. What are the colors of the indicators in this solution?

Choices

Choice (4) Response

a.

Image showing solution of pH2: Choice A

Image Showing Solution of pH2: Choice A

Image showing solution of pH2

b.

Image showing solution of pH2: Choice B

Image Showing Solution of pH2: Choice B

Image showing solution of pH2

c.

Image showing solution of pH2: Choice C

Image Showing Solution of pH2: Choice C

Image showing solution of pH2

d.

Image showing solution of pH2: Choice D

Image Showing Solution of pH2: Choice D

Image showing solution of pH2

Answer

d.

Explanation

Correct option is means acidic substance so bromophenol blue turns to yellow as above data. And congo red to violet

Question number: 25

MCQ▾

Question

Atomicity only appears for ________.

Choices

Choice (4) Response

a.

Elements

b.

Compounds

c.

Both a. and b. are correct

d.

None of the above

Answer

c.

Explanation

  • The number of atoms of an element that join together to form a molecule of that element is known as atomicity of that molecule.

  • The smallest part of an element is atom. But the smallest part of a compound is molecule which exhibits all the chemical nature a compound shows.

Question number: 26

Short Answer Question▾

Write in Short

Malonic acid is a white crystalline solid which is soluble in water. It melts at 135 °C. The structural formula of malonic acid is given below. It forms salts called malonates

What is the molecular formula of malonic acid?

Explanation

Molecular formula of malonic acid is .