Question

Hydrogen and oxygen combine in the ratio of 1 : 8 by mass to form water. What mass of oxygen gas would be required to react completely with 3 g of hydrogen gas?​

Answer 1

Solution :-

It is given that the ratio of hydrogen and oxygen by mass to form water is 1 : 8. Then, the mass of oxygen gas required to react completely with 1 g of hydrogen gas is 8 g. Therefore, the mass of oxygen gas required to react completely with 3 g of hydrogen gas is 8 × 3 g = 24 g.

Answer 2

• Since, the ration by which oxygen and hydrogen combine to give water is 1:8.
• We can take it as "1g of hydrogen combines with 8g oxygen to give water''
• So, 3g of hydrogen will combine with 3×8=24g of oxygen to give water