If for a first order reaction, the value of $ A $ and $ E_{a} $ are $ 4 \times 10^{13} \mathrm{~s}^{-1} $ and $ 98.6 \mathrm{~kJ} \mathrm{~mol}^{-1} $ respectively, then at what temperature will its half life period be 10 minutes?

A tetrapeptide is made of naturally occuring alanine, serine, glycine and valine. If the $ C $-terminal amino acid is alanine and N-terminal amino acid is chiral, the number of possible sequence of the tetrapeptide is

In the following species, how many species have same magnetic moment?

(i) $ \mathrm{Cr}^{2+} $ (ii) $ \mathrm{Mn}^{3+} $ (iii) $ \mathrm{Ni}^{3+} $ (iv) $ \mathrm{Sc}^{2+} $ (v) $ \mathrm{Zn}^{2+} $ (vi) $ \mathrm{V}^{3+} $ (vii) $ \mathrm{Ti}^{+} $

The spin only magnetic moment of $ \mathrm{Fe}^{3+} $ ion (in BM) is approximately.