Write the names of the metric system units given. Spelling counts.

The time taken for the cross to disappear decreases as we move down the table

Explanation:

We have to take note of three important things we can see in the table.

1) the volume of HCl was held constant

2) the volume of the thiosulphate solution was increased steadily down the table

3) the volume of water was decreased steadily down the table.

We know that the rate of reaction increases with increase in the the concentration of reactants. The more the volume of reactants compared to the volume of the volume of water present, the higher the concentration of reactants and the faster the rate of reaction. This implies that it takes a shorter time for the reaction to get to completion.

As we increase the volume of thiosulphate and decrease the volume of water, we are manipulating the reactant concentration. In this case, concentration is being increased. Hence the reaction proceeds faster and it takes a shorter time for the cross to disappear. Hence the time taken for the cross to disappear will decreased steadily down the table.