Explanation:
(a) As the given chemical reaction equation is as follows.

So, when we double the amount of hypochlorite or iodine then the rate of the reaction will also get double. And, this reaction is "first order" with respect to hypochlorite and iodine.
Hence, equation for rate law of reaction will be as follows.
Rate =
(b) Since, the rate equation is as follows.
Rate =
Let us assume that (
)
Putting the given values into the above equation as follows.

K =
=
Hence, the value of rate constant for the given reaction is
.
(c) Now, we will calculate the rate as follows.
Rate =
=
= 
Therefore, rate when
M and
M is
.
Answer:

Explanation:
Hello,
In this case, the only source of hydrogen is in the 6 molecules of water, therefore, the atoms of hydrogen, by applying stoichiometry with the Avogadro's number is:

Best regards.
V = 500ml = 0,5 l
c = 0,75 M
c = n/V
n = c × V
n = 0,75 × 0,5 = 0,375[mol]
M NaCl = 58,5 g/mol
1 mol ------- 58,5 g
0,375 mol ----- x g
x = 0,375 mol × 58,5 g / 1 mol = 21,94 g
Answer: In this solution there are 21,94 g of sodium chloride.
:-) ;-)