Question

the temperature of ice can be decreased below 0C by mixing................... in it
1)saw dust
2)sand
3)salt
4)coal

Answer 1

the temperature of ice can be decrease below 0℃ by mixing salt  in it

Answer 2

The temperature of ice can be decreased below $0^{\circ} \mathrm{C}$ by mixing salt in it.

Answer - (Option 2)

Explanation:

• Salt lowers the temperature of the ice or ice water from $0^{\circ} \mathrm{C}$ to subzero temperatures.
• This action occurs because salt depresses the freezing point of water and reduce the temperature much below it. This point is called freezing point depression.
• Since the salt ion gets its way into water molecules, water molecules tend to crystallize to form ice.
• Using this principle, even without a refrigerator, ice creams can be made by keeping the mixture in a bowl of salted ice.