I am pretty sure the answer is B but correct me if I'm wrong hope this helps.
Steel is an alloy and consists of more than one element (mainly iron and carbon), therefore steel is a mixture.
<u>We are given:</u>
Mass of ice = 21 grams
The ice is already at 0°c, the temperature at which it melts to form water
Molar heat of fusion of Ice = 6.02 kJ/mol
<u>Finding the energy required:</u>
<u>Number of moles of Ice: </u>
Molar mass of water = 18 g/mol
Number of moles = given mass/ molar mass
Number of moles = 21 / 18 = 7/6 moles
<u>Energy required to melt the given amount of ice:</u>
Energy = number of moles * molar heat of fusion
Energy = (7/6) * (6.02)
Energy = 7.02 kJ OR 7020 joules
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
.
1,6,1,2 that should be the answer