Which of the following is an emulsifier?

$1+\frac{1}{3 \cdot 2^2}+\frac{1}{5 \cdot 2^4}+\frac{1}{7 \cdot 2^6}+\ldots$ is equal to

Identify the logic operation carried out by the following circuit.

The temperature of $5$ moles of a gas at constant volume is changed from $100^{\circ} C$ to $120^{\circ} C$. The change in internal energy is $80 \ J$. The total heat capacity of the gas at constant volume in $J/K$ is:

Which of the following compound$(s)$ has '$Z$' configuration?

Sulphur trioxide is dissolved in heavy water to form a compound $X$. The hybridisation state of sulphur in $X$ is :