Exercise :
Class 10 Science Chapter 2 MCQs — General Questions
1.
A solution turns red litmus blue, its pH is likely to be:
A
1
B
4
C
5
D
10
Answer:
D
Explanation:
A solution that turns red litmus paper blue is basic (alkaline) in nature.
On the pH scale:
Acids → pH less than 7
Neutral → pH = 7
Bases (alkalis) → pH greater than 7
Since the solution is basic, its pH is greater than 7, typically between 8 and 14.
So, the likely pH is above 7.
2.
A solution reacts with crushed egg-shells to give a gas that turns lime-water milky.
The solution contains:
A
NaCl
B
HCl
C
LiCl
D
KCl
Answer:
B
Explanation:
HCl – Acid (reacts with CaCO₃ to give CO₂)
3.
10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, the amount of HCl solution (the same solution as before) required to neutralise it will be:
A
4 mL
B
8 mL
C
12 mL
D
16 mL
Answer:
D
Explanation:
Neutralisation reaction:
NaOH+HCl→NaCl+H₂O
The reaction ratio between NaOH and HCl is 1 : 1.
Given:
10 mL NaOH requires 8 mL HCl.
If the volume of NaOH is doubled (20 mL), the amount of HCl required will also double (since concentration remains same).
8 mL×2=16 mL
4.
Which one of the following types of medicines is used for treating indigestion?
A
Antibiotic
B
Analgesic
C
Antacid
D
Antiseptic
Answer:
C
Explanation:
Antacids are medicines used to treat indigestion and heartburn. During indigestion, the stomach produces an excess amount of hydrochloric acid, which causes pain and irritation.