I would say the second option
Hope this helps *smiles*
Hey there!:
HCl + MnO2 → MnCl2 + H2O + Cl2
* in HCl the oxidation state of Cl is -1 .
* on the product side the oxidation state is 0 .
* therefore Cl gains electrons .
* in MnO2 the oxidation state of Mn is +4
* in MnCl2 the oxidation state of Mn is +2
Therefore Mn loses electrons
Answer A
Hope That helps!
4 mol NH₃ → 5 mol N₂
x mol NH₃ → 0.824 mol N₂
x=0.824*4/5=0.6592 mol