for 12th question , write the half cell reaction ( which is given in ques 6 ) .
for every 1 mole of Pb , 2 moles of electrons are required, or for every 2 moles of H2SO4 , 2 moles of electrons are required( comparing with cathodic half cell ).
so simply finding the moles of electrons will give the answer.( current*time / 96500 )
similarly for question 6.