Answer :
We have ,
[tex]\begin{gathered} C=\frac{Q}{V} \\ C=capacitance; \\ Q=charge; \\ V=\text{ potential difference;} \end{gathered}[/tex]Using above formula for first case
[tex]\begin{gathered} C1=\text{ }\frac{Q0}{V}; \\ \therefore V=\text{ }\frac{Q0}{C1} \end{gathered}[/tex]Now equivalent capacitance(C) of combination is given by
[tex]\begin{gathered} \frac{1}{C}=\frac{1}{C1}+\frac{1}{C2}; \\ \therefore C=\frac{C1C2}{C1+C2}; \end{gathered}[/tex]Now for second case , let Q= required charge
[tex]\begin{gathered} Q=\text{ CV;} \\ \therefore Q=\text{ }\frac{C1C2}{C1+C2}\times\frac{Q0}{C1};\begin{cases}C={\frac{C1C2}{C1+C2}} \\ V={\frac{Q0}{C1}}\end{cases} \\ \\ \therefore Q=\frac{C2}{C1+C2}\times Q0 \end{gathered}[/tex]a) Charge is given by
[tex]\frac{C2}{C1+C2}Q0[/tex]b) Potential difference is
[tex]V1=\text{ }\frac{Q0}{C1}\text{ \& V2= }\frac{Q0}{C2}[/tex]