Question

Which of the following equations is balanced for charge and mass?

A. S(s) + 2H+ H2S(g) + 2e–
B. S(s) + 2H+ + 2e– H2S(g)
C. S(s) + 2e- H2S(g)
D. S(s) + 2H+ H2S(g)

Answer 1

B. S⁰(s) + 2H⁺ + 2e⁻ –--> H2S⁰(g)

by mass: 1 S and 2 H ----> 2 H and 1S True.
by charge : 0 +(2*(+1)) + 2*(-1) = 0, 0+2-2=0, 0 = 0 True.

Answer 2

The following equation(option B) is balanced for charge and mass

A. S(s) + 2H+ → H2S(g) + 2e–

B. S(s) + 2H+ + 2e– → H2S(g)

C. S(s) + 2e- →H2S(g)

D. S(s) + 2H+→ H2S(g)

S(s) + 2H+ + 2e– → H2S(g)

here S is one on either sides

H is two on either sides, hence mass is balanced.

And charge is also balanced,

as 2H+ has +2 charge

and 2e- has -2 charge,thus

total charge on left side is +2-2 = 0

and charge on right side is also zero here or no charge on either sides.