In an isothermal process,which statement is wrong?

During an isothermal expansion,a confined ideal gas does $-150 \, J$ of work against its surroundings. This implies that

An ideal gas is subjected to an isothermal expansion such that its volume changes from $V_i$ to $V_f$ and pressure from $P_i$ to $P_f$. The work done on the gas is:

Heat is given to an ideal gas in an isothermal process. Then

$A$ vertical cylinder with heat-conducting walls is closed at the bottom and is fitted with a smooth light piston. It contains one mole of an ideal gas. The temperature of the gas is always equal to the surrounding's temperature,$T_0$. The piston is moved up slowly to increase the volume of the gas to $\eta$ times. Which of the following is incorrect?

One mole of an ideal monoatomic gas is compressed isothermally in a rigid vessel to double its pressure at room temperature,$27\,^{\circ}C$. The work done on the gas will be