Which of the following is different from the other three oxides?

Two cylinders $A$ and $B$ fitted with pistons contain equal number of moles of an ideal monoatomic gas at $400 ~K$. The piston of $A$ is free to move while that of $B$ is held fixed. Same amount of heat energy is given to the gas in each cylinder. If the rise in temperature of the gas in $A$ is $42 ~K$, the rise in temperature of the gas in $B$ is (in $~K$)

If $\alpha, \beta$ and $\gamma$ are the lengths of the altitudes of a $\triangle ABC$ with area $\Delta$,then $\frac{\Delta^2}{R^2}\left(\frac{1}{\alpha^2}+\frac{1}{\beta^2}+\frac{1}{\gamma^2}\right)$ is equal to

At $298 \ K$,the $emf$ of the cell is .......... $V$.
$Pt | H_{2(2 \ atm)} | H^{+}_{(0.002 \ M)} || H^{+}_{(0.1 \ M)} | H_{2(1 \ atm)} | Pt$

What is the chemical nature of alane?

What is the output $Y$ in the following circuit,when all the three inputs $A, B, C$ are first $0$ and then $1$?