IGCSE Chemistry Paper-1: Specimen Questions with Answers 97 - 98 of 99

Question number: 97

Edit
MCQ▾

Question

ph of some solutions is given in below table. What would be the nature of the substance.

pH of solutions is given in table

Find which is acidic or basic in nature

S. No.

Solution

App pH value

1

Coffee

4.5 - 5.5

2

Soapy water

12

3

Saliva

6.5 – 7.5

4

Battery acid

0

Choices

Choice (4)Response

a.

1- Basic, 2- Neutral, 3 –Neutral, 4 –Acidic

b.

1- Basic, 2- Acidic, 3 –Neutral, 4 -Acidic

c.

1- Acidic, 2- Basic, 3 –Neutral, 4 -Acidic

d.

1- Basic, 2- Neutral, 3 –Neutral, 4 -Basic

Answer

c.

Explanation

pH is a numeric scale used to specify the acidity or alkalinity of an aqueous solution Solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are alkaline or basic. Pure water is neutral, being neither an acid nor a base. Contrary to popular belief, the pH value can be less than 0 or greater than 14 for very strong acids and bases respectively.

Question number: 98

Edit
MCQ▾

Question

Which of the following is a precipitation reaction?

Choices

Choice (4)Response

a.

AgNO₃+NaCl AgCl + NaNO₃

b.

Zn + CuSO₄ + ZnSO₄ + Cu

c.

HCl + NaOH NaCl + H₂O

d.

Question does not provide sufficient data or is vague

Answer

a.

Explanation

A precipitate is a solid that forms out of solution. A common example is that of the mixing of two clear solutions: (1) silver nitrate (AgNO3) and (2) sodium chloride (NaCl): The reaction is.

AgNO₃+NaCl AgCl + NaNO₃

The precipitate forms because the solid (AgCl) is insoluble in water.

Developed by: