A) What gas is collected in the gas jar? b) Write the balanced chemical equation. c) What happens if concentrated H2SO4 is used instead of dilute acid?

Here are the answers to question 30:

30.

a) The gas being collected in the gas jar is hydrogen gas ($\text{H}_2$).

b) The balanced chemical reaction involved in this process is:

$$\text{Zn(s)} + \text{2HCl(aq)} \longrightarrow \text{ZnCl}_2\text{(aq)} + \text{H}_2\text{(g)}$$

c) If concentrated $\text{H}_2\text{SO}_4$ is used instead of dilute acid, sulfur dioxide gas ($\text{SO}_2$) will be formed. Concentrated sulfuric acid acts as an oxidizing agent, reacting with zinc to produce sulfur dioxide, zinc sulfate, and water.