Which of the following is NOT a method to purify water? MCQ with Answer and Explanation

Which of the following is NOT a method to purify water?
A. UV irradiation
B. Distillation
C. Electrolysis
D. Reverse osmosis
Answer: Option C
Solution (By JKExamLibrary)
Electrolysis of water splits it into hydrogen and oxygen, it is not a purification method but a decomposition. Reverse osmosis uses semipermeable membrane to remove ions and impurities. UV irradiation kills microorganisms. Distillation boils water and condenses steam, removing non-volatile impurities. Other methods: filtration, chlorination, ozonation, boiling.

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Practice More chemistry Questions

Question #1
Distillation is a method of purification that removes:
A. Dissolved gases and volatile impurities
B. All microorganisms
C. Suspended solids
D. Only color

Correct Answer: Option A


Explanation:
Distillation involves boiling and condensation, separating non-volatile impurities (salts) and some volatile impurities. It can also kill microorganisms but boiling already does; distillation purifies further.

This question belongs to: Science chemistry
Question #2
Which of the following elements is a metalloid?
A. Chlorine
B. Germanium
C. Sodium
D. Aluminium

Correct Answer: Option B


Explanation:
Germanium (Ge) is a metalloid, exhibiting properties of both metals and non-metals. It is a semiconductor used in transistors. Sodium and aluminium are metals. Chlorine is a non-metal. Metalloids are located along the zigzag line in the p-block.

This question belongs to: Science chemistry
Question #3
The half-life of a radioisotope is the time required for its activity to reduce to:
A. Zero
B. One-half of the initial value
C. Three-fourths
D. One-fourth

Correct Answer: Option B


Explanation:
Half-life (T₁/₂) is the time taken for the number of radioactive nuclei (or activity) to decrease to half of its original value. It's a constant characteristic of each radioisotope. For example, C-14 half-life is 5730 years.

This question belongs to: Science chemistry