Question

Balance the following equations:

$A{g}^{+}+As{H}_3\to H_{3}As{O}_3+H^{+}+.......$

• A. $6A{g}^{+}+As{H}_3+3H_{2}O\to 6Ag+6H^{+}+H_{3}As{O}_3$
• B. $6A{g}^{+}+As{H}_3+H_{2}O\to 4Ag+6H^{+}+H_{3}As{O}_3$
• C. $6A{g}^{+}+As{H}_3+H_{2}O\to 6Ag+H^{+}+H_{3}As{O}_3$
• D. None of these

Answer 1

The correct option is A $6A{g}^{+}+As{H}_3+3H_{2}O\to 6Ag+6H^{+}+H_{3}As{O}_3$

The unbalanced redox equation is as follows:
$A{g}^{+}+As{H}_3\to H_{3}As{O}_3+H^{+}$
Balance all atoms other than H and O.
$A{g}^{+}+As{H}_3\to H_{3}As{O}_3+H^{+}+Ag$
The oxidation number of Ag changes from +1 to 0. The change in the oxidation number of Ag is 1.
The oxidation number of As changes from -3 to +3. The change in the oxidation number of As is 6.
The increase in the oxidation number is balanced with decrease in the oxidation number by multiplying $A{g}^{+}$ and $Ag$ with 6.
$6A{g}^{+}+As{H}_3\to H_{3}As{O}_3+H^{+}+6Ag$
O atoms are balanced by adding 2 water molecule on LHS.
$6A{g}^{+}+As{H}_3+3H_{2}O\to H_{3}As{O}_3+H^{+}+6Ag$
Hydrogen atoms are balanced by adding 5 $H^{+}$ atoms on the RHS.
$6A{g}^{+}+As{H}_3+3H_{2}O\to H_{3}As{O}_3+6H^{+}+6Ag$
This is the balanced chemical equation.