Question

During an experiment hydrogen (H₂) and oxygen (O₂) gases reacted in an electric are to produce water as

follows: 2H +O₂ \(\overset{Electicity}{\longrightarrow}\) 2H₂O

The experiment is repeated three times and data tabulated as shown below:

Experiment number	Mass of H2 reacted	Mass of O2 reacted	Mass f H2O produced
1	2g	16g	18g
2	4g	32g	36g
3	-	-	9g

During 3^rd experiment the researcher forgot to list masses of H₂ and O₂ used. So, if the law of constant proportion is correct then ind mass of O₂ used during 3_rd experiment. 

A. 4g B. 8g C. 16g D. 32g

Answer 1

In experiment (i), the ratio is 2:16, i.e., 1:8 

In experiment (ii), the ratio is 4:32, i.e., 1:8 

According to the law of constant proportions, the ratio of third experiment should be the same (1:8) 

Therefore, the mass of O₂ used during 3^rd experiment is 8g.