The yellow colour solution of $Na_2CrO_4$ changes to orange-red on passing $CO_2$ gas due to the formation of

The freezing point of a $1.00 \, m$ aqueous solution of $HF$ is $-1.91^o C$. The freezing point depression constant of water $K_f$ is $1.86 \, K \, kg \, mol^{-1}$. The percentage of dissociation of $HF$ at this concentration is ......... $\%$

Evolutionary classification is called ........

If $\sin (y+z-x), \sin (z+x-y)$ and $\sin (x+y-z)$ are in $AP$,then

In the diagram,$I_1$ and $I_2$ are the strengths of the currents in the loop and the infinitely long straight conductor,respectively. Given $OA = AB = R$. The net magnetic field at the centre $O$ is zero. Then the ratio of the currents in the loop and the straight conductor $(I_1/I_2)$ is:

The acrosome of a sperm contains: