Hope this helps! Na+ lost an electron, so I just left a "+" symbol to show that, and fluorine gained an electron, hence the "-" symbol.
We have to know final temperature of the gas after it has done 2.40 X 10³ Joule of work.
The final temperature is: 75.11 °C.
The work done at constant pressure, W=nR(T₂-T₁)
n= number of moles of gases=6 (Given), R=Molar gas constant, T₂= Final temperature in Kelvin, T₁= Initial temperature in Kelvin =27°C or 300 K (Given).
W=2.4 × 10³ Joule (Given)
From the expression,
(T₂-T₁)=
(T₂-T₁)= 
(T₂-T₁)= 48.11
T₂=300+48.11=348.11 K= 75.11 °C
Final temperature is 75.11 °C.
Moles of ZnSO4 = Mass/Mr
= 2/(65.4 + 32.1 + (16 x 4))
= 0.012383.... mol
Since there is no chemical equation provided, I will assume that the ratio of ZnSO4:Li2CO3 is 1:1
Therefore there are 0.012383 mil of Li2SO4 as well
So the mass would be Moles x Mr = 0.012383.... x ((6.9 x 2) +32.1 + (4x16))
= 1.360 g of Li2SO4 produced
C the products are on the right side of the arrow
The oxidation number of chlorine can be determined by identifying first the oxidation numbers of oxygen and Na. Oxygen has a charge of -2 and has a total of -8. Na has +1. To make the total zero, Cl has to have a charge of +7.