The reaction between solid sodium carbonate and dilute nitric acid is investigated at 298 K:
Na2CO3(s)+2HNO3(aq)→2NaNO3(aq)+H2O(l)+CO2(g) \text{Na}_2\text{CO}_3(\text{s}) + 2\text{HNO}_3(\text{aq}) \rightarrow 2\text{NaNO}_3(\text{aq}) + \text{H}_2\text{O}(\text{l}) + \text{CO}_2(\text{g}) Na2CO3(s)+2HNO3(aq)→2NaNO3(aq)+H2O(l)+CO2(g)Which of the following modifications will decrease the initial rate of this reaction?
Replacing 50 cm350\text{ cm}^350 cm3 of 1.0 mol dm−3 HNO31.0\text{ mol dm}^{-3}\ \text{HNO}_31.0 mol dm−3 HNO3 with 100 cm3100\text{ cm}^3100 cm3 of 0.5 mol dm−3 HNO30.5\text{ mol dm}^{-3}\ \text{HNO}_30.5 mol dm−3 HNO3.
Carrying out the reaction at 308 K308\text{ K}308 K instead of 298 K298\text{ K}298 K.
Crushing the sodium carbonate crystals into a fine powder before adding them to the acid.
Performing the reaction in a vessel with a larger volume, thereby lowering the partial pressure of CO2(g)\text{CO}_2(\text{g})CO2(g) above the mixture.