The water can be made to boil even at $0$°C if the pressure of surrounding is _____.

Soap solution used for cleaning purpose appears cloudy. This is due to the fact that soap micelles can _____.

The instrument used to regulate temperature to a particular degree is called:

1. Thermostat

2. Thermometer

3. Pyrometer

4. Thermocouple

Which of the following substances cause temporary hardness in water?

$1. Mg{\left(HC{O}_3\right)}_2$

$2. Ca{\left(HC{O}_3\right)}_2$

$3. CaC{l}_2$

$4. MgS{O}_4$

Select the correct answer using the code given below.