Which of the following is an amphoteric oxide?

The half-life period of a radioactive element $X$ is the same as the mean lifetime of another radioactive element $Y$. Initially, both of them have the same number of atoms. Then:

If the vertex of the conic $y^{2}-4y=4x-4a$ always lies between the straight lines $x+y=3$ and $2x+2y-1=0$, then

Which one of the following conditions is incorrect for a well-behaved wave function $(\psi)$?

Which of the following orders is not correct?

In the $Hoop$ process for the refining of $Al$,the molten materials form three different layers and remain separate during electrolysis because ..........