Answer:
8
Explanation:
Oxidation:

Reduction:

We have to equalise the number of moles of electrons gained and lost in a redox reaction in order to get a balanced reaction.
Hence we have to multiply the oxidation reaction throughout by 6.
and adding the two half-reactions we obtain:

Still the total charge and number of oxygen is not balanced.
Since the reaction takes place in acidic conditions, we will add required number of H+ to the appropriate side to balance the charge and add half the amount of H2O to balance the hydrogen atoms.
We add 14 H+ on LHS and 7H2O on RHS to obtain:

Sum of coefficients of product cations = 6+2 = 8
Answer:a) 0.1 mole. b) 4g. c) 2% d) 196 mL
Explanation: in 200mL , 0.1mole
mw NaOH = 40g/mol —> 4g in 0.1 mole
4g in 200mL so 2g in 100mL
density NaOH = 1g/mL so if 4g in 200 mL, 4mL , 196 mL water
The first answer choice would be more conservative to our environment