Question

IF 9 g of H2O is electrolysed completely with 50% current efficiency :

1) 1F of electricity will be needed

2) 3 F of electricity will be needed

3) 5.6 l of O2 will be formed at STP

4) 11.2l of O2 will be formed at STP

PLEASE EXPLAIN THE ANSWER STEP BY STEP?????

Answer 1

Given:

Quantity of H2O = 9g

Efficiency = 50%

To Find:

The STP formed

Solution:

Number of moles of water = Weight given/molecular weight

= 9/18

= 0.5mol

The equation for electrolysis of water is -  

2H2O→ 2H​2+O2

Thus, at STP two moles of water dissociate to produce one mole of oxygen

However, at STP 0.5 moles of water will produce only 0.25 mole of oxygen

Now,

One mole of oxygen will occupy = 22.4 litres of oxygen

Then 0.25 mole of oxygen will occupy

= 0.25 × 22.4

=5.6

Answer: Thus, 5.6 l of O2 will be formed at STP

Answer 2

Answer:

11.2L

Explanation:

now,water electrolysis:

H₂O→1/2O₂+ H₂

therefore,1 mole produces 1/2 mole of O₂ .

9/18=0.5mole produces 0.25 mole which is equal to 22.4×0.25=5.6L

but due to 50%efficency volume is equal to 11.2L