For a first order reaction, the half life is inversely proportional to the rate constant.
The formula is
half life = ln(2)/k = 0.693/k
where k is the rate constant
t = 5.50 minutes
k = ln(2)/5.50 = 0.126 min^-1
Your rate constant is 0.126 min^-1.
C- Sugar is very much soluble (example- putting sugar in tea), sand is definately not soluble (example- a sandy beach) and cornstarch is the last one, so logically it should be somewhat soluble.
6 ( tell me if you got it right)
