Question 6
A reaction forms a precipitate. Which is the most suitable way to measure its rate?
The right answer is the one marked above.
Timing how long the clouding solution takes to hide a mark placed underneath it. That is a measure of how fast the precipitate is forming.
Weighing once gives no change at all — a rate needs two readings. Neither the height of the beaker nor the names of the reactants alters as the reaction proceeds.