Can someone please help me with these Chemistry questions?

Question

For the following questions, use the following: Chlorine is used to bleach cloth. Excess Chlorine is destroyed by its reaction with Sodium Thiosulfate (Na₂S₂O₃) according to the unbalanced equation Na₂S₂O₃ + Cl₂ + H₂O → NaHSO₄ + HCl.

* How many moles of Na₂S₂O₃ are needed to react with 0.40 moles of Cl₂?

A. 0.10 mol Na2S2O3

B. 0.20 mol Na2S2O3

C. 0.30 mol Na2S2O3

D. 0.40 mol Na2S2O3

E. 0.50 mol Na2S2O3

* How many moles of HCl can be formed from 0.25 moles of Cl₂?

A. 0.10 mol HCl

B. 0.20 mol HCl

C. 0.30 mol HCl

D. 0.40 mol HCl

E. 0.50 mol HCl

* How many moles of H₂O react if 0.48 moles of HCl is formed?

A. 0.10 mol H2O

B. 0.20 mol H2O

C. 0.30 mol H2O

D. 0.40 mol H2O

E. 0.50 mol H2O

Answer 1

Na₂S₂O₃ + Cl₂ + H₂O → NaHSO₄ + HCl ... unbalanced equation.

Of course, we must balance this redox equation before answering the questions.

S₂O₃^2- +5H₂O ==> 2HSO₄^- + 8H⁺ + 8e- oxidation half reaction

Cl₂ + 2e- ==> 2Cl- [x4] reduction half reaction

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S₂O₃^2- +5H₂O + 4Cl₂ + 8e- ==> 2HSO₄^- + 8H⁺ + 8e- + 8Cl^-

Na₂S₂O₃ + 4Cl₂ + 5H₂O ==> 2NaHSO₄ + 8HCl ... balanced equation

How many moles of Na₂S₂O₃ are needed to react with 0.40 moles of Cl₂?

0.4 mol Cl2 x 1 mol Na₂S₂O₃ / 4 mol Cl2 = 0.10 moles (ANSWER A)

How many moles of HCl can be formed from 0.25 moles of Cl₂?

0. 25 mol Cl₂ x 8 mol HCl / 4 mol Cl₂ = 0.5 moles HCl (ANSWER E)

How many moles of H₂O react if 0.48 moles of HCl is formed?

0.48 mol HCl x 5 mol H₂O /8 mol HCl = 0.3 moles H₂O (ANSWER C)

Hope this all makes sense to you.