Question

Water is used to cool down automobile engines when they get hot. Why is water used as a coolant?

Answer 1

The answer is D) Water has a high heat capacity.

Answer 2

Explanation :

Water is used to cool down automobile engines when they get hot. It is used as a coolant because it has a high heat capacity. It is approximately equal to $4.186\ J/g\ ^0C$.

The heat capacity of a substance is defined as the change in temperature due to the addition and removal of heat. Its SI unit is joule per kelvin. It is also an extensive property of matter.

The specific heat of water shows that each gram of water can absorb or release 4.186 joules of heat.  

In the case of water, it will soak up a large amount of heat and its do not increase by very large amount.

So, the correct option is (d) "Water has a high heat capacity".