Question

While lighting a candle, Paheli observed the following changes. (i) Wax was melting (ii) Candle was burning (iii) Size of the candle was reducing (iv) Melted wax was getting solidified Of the above, the changes that can be reversed are

• A. (i) and (ii)
• B. (ii) and (iii)
• C. (iii) and (iv)
• D. (i) and (iv)

Answer 1

The correct option is D

(i) and (iv)

Explanation for the correct answer:-

Option (D) (i) and (iv)

• As the wax is melting, it can be solidified again.
• On the other hand the meted wax is getting solidified.
• Thus both this solidification and melting of wax are reversible changes.
• Hence it s the correct option.

Explanation for the incorrect answer:-

Option (A) (i) and (ii)

• As the wax is melting, it can be solidified again.
• Burning of a candle is considered to be a chemical change.
• That is it cannot be reversed, as the oxygen around the candle reacts, which results in the formation of Carbon dioxide$\left({\mathrm{CO}}_2\right)$
• Hence it is the incorrect option.

Option (B) (ii) and (iii)

• Burning of a candle is considered to be a chemical change, which is a reversible process.
• That is it cannot be reversed, as the oxygen around the candle reacts, which results in the formation of Carbon dioxide$\left({\mathrm{CO}}_2\right)$
• As the candle burns, the size of the candle begins to get smaller.
• This cannot be reversed and hence is a chemical change.
• Hence it is the incorrect option.

Option (C) (iii) and (iv)

• As the candle burns, the size of the candle begins to get smaller.
• This cannot be reversed and hence is a chemical change.
• The meted wax is getting solidified which is a reversible process.
• Hence it is the incorrect option.

Therefore, option (D) (i) and (iv) is the correct option.