Sporeine was developed in

The sulphate of a metal $M$ contains $9.87 \%$ of $M$. This sulphate is isomorphous with $ZnSO_4 \cdot 7H_2O$. The atomic weight of $M$ is: (in $.3$)

If $x_n = \cos \left(\frac{\pi}{4^n}\right) + i \sin \left(\frac{\pi}{4^n}\right)$,then the product $x_1 x_2 x_3 \ldots \infty$ is equal to

The number of $5$-digit numbers that are not divisible by $5$ and consist of different odd digits is:

In the reaction of $BaO_2$ with dilute $H_2SO_4$,what are the oxidation states of the most electronegative element in the products?

The sum of the spin only magnetic moment values $(in \ B.M.)$ of $\left[ Mn ( Br )_6\right]^{3-}$ and $\left[ Mn ( CN )_6\right]^{3-}$ is $....$ .