If the activity of a sample of 232Th decreases from 1000 cpm to 500 cpm in 60 min, in another 60 min its activity will be O O cpm.
500 cpm.
O 125 cpm.
0 250 cpm.

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.

the answer is c.the valence of the atoms combine .