Which element among the alkaline earth metals primarily forms covalent compounds?

When carbon monoxide is passed over solid caustic soda heated to $200^\circ C$,it forms

Among the given cations,the most stable carbonium ion is?

The value of electric potential at any point due to an electric dipole is

Two moles of ideal helium gas are in a rubber balloon at $30^\circ C$. The balloon is fully expandable and can be assumed to require no energy in its expansion. The temperature of the gas in the balloon is slowly changed to $35^\circ C$. The amount of heat required in raising the temperature is nearly...... $J$ (take $R = 8.31$ $J/mol \cdot K$)

In a fission reaction $_{92}^{236}U \to ^{117}X + ^{117}Y + n + n$,the binding energy per nucleon of $X$ and $Y$ is $8.5\, MeV$,whereas that of $^{236}U$ is $7.6\, MeV$. The total energy liberated will be about: