60cm 3 ?of hydrogen are sparked with 20cm 3 of oxygen at 100° and atmosphere.

Explanation

When hydrogen and oxygen react together, they form water. The balanced chemical equation for this reaction is:

\[\text{2H}_2(g) + \text{O}_2(g) \rightarrow 2\text{H}_2\text{O}(g)\]

From this equation, we can see that 2 moles of hydrogen react with 1 mole of oxygen to form 2 moles of water vapor. Now let's apply this to the given volumes:

We have 60 cm\(^3\) of hydrogen and 20 cm\(^3\) of oxygen. We will use the ratio of 2:1 from the balanced equation to determine the limiting reactant:

\[\frac{60}{2} = 30\] and \[\frac{20}{1} = 20\]

Since 20 is less than 30, oxygen is the limiting reactant.

Now let's determine the volume of residual gases. Since 2 moles of hydrogen react with 1 mole of oxygen, 40 cm\(^3\) of hydrogen will react completely with the 20 cm\(^3\) of oxygen:

\[60\text{ cm}^3_{\text{H}_2} - 40\text{ cm}^3_{\text{H}_2} = 20\text{ cm}^3_{\text{H}_2}\]

There is no residual oxygen left, as it has all reacted with the hydrogen. Therefore, the total volume of residual gases is the sum of the unreacted hydrogen and the water vapor produced:

\[20\text{ cm}^3_{\text{H}_2} + 40\text{ cm}^3_{\text{H}_2\text{O}} = 70\text{ cm}^3\]

The correct answer is Option D: 70 cm\(^3\).