Time required for $$90 \%$$ completion of a first order reaction is $$t$$. What is the time required for completion of $$99 \%$$ reaction?

A weak monobasic acid is $$3.0 \%$$ dissociated in it's $$0.04 \mathrm{~M}$$ solution. What is the dissociation constant of acid?

Which of the following alkanes is optically active?

Identify the number of unpaired electrons present and geometry respectively of [Co(NH$$_3$$)$$_6$$]$$^{3+}$$ complex.