This question requires use of the Data Booklet. The table below shows the approximate percentage composition of the atmosphere on four different planets. The density of a gas can be defined as the mass of $1\,\text{dm}^3$ of that gas measured at s.t.p. Which gas mixture has the highest density?
- AJupiter: $\text{H}_2$ 89.8%, He 10.2%
- BNeptune: $\text{H}_2$ 80.0%, He 19.0%, $\text{CH}_4$ 1.0%
- CSaturn: $\text{H}_2$ 96.3%, He 3.25%, $\text{CH}_4$ 0.45%
- DUranus: $\text{H}_2$ 82.5%, He 15.2%, $\text{CH}_4$ 2.3%