If a refrigerator's door is opened in a closed room,then we get:

Arrange the following in order of magnitude of work done by the system / on the system at constant temperature:
$(a)$ $|w_{reversible}|$ for expansion in infinite stage.
$(b)$ $|w_{irreversible}|$ for expansion in single stage.
$(c)$ $|w_{reversible}|$ for compression in infinite stage.
$(d)$ $|w_{irreversible}|$ for compression in single stage.
Choose the correct answer from the options given below:

The amount of heat evolved when $500 \ cm^{3}$ of $0.1 \ M \ HCl$ is mixed with $200 \ cm^{3}$ of $0.2 \ M \ NaOH$ is (in $kJ$)

For an isothermal expansion of $2 \, \text{mol}$ of a gas at $298 \, K$ from $5 \, dm^3$ to $40 \, dm^3$ under constant external pressure,the work done $(W)$ and the reversible work $(W_{rev})$ are,respectively:

One mole of $CH_3OH$ is vaporized at $338 \ K$ and $1.5 \ atm$ pressure. If the enthalpy of vaporization of $CH_3OH$ is $35.57 \ kJ/mol$,calculate the value of $\Delta U$ for the process in $kJ$. (in $.76$)

$A$ solution of $500 \ mL$ of $0.2 \ M \ KOH$ and $500 \ mL$ of $0.2 \ M \ HCl$ is mixed and stirred; the rise in temperature is $T_1$. The experiment is repeated using $250 \ mL$ each of solution,the temperature raised is $T_2$. Which of the following is true?