<u>Answer:</u> The value of
for the net reaction is 
<u>Explanation:</u>
The given chemical equations follows:
<u>Equation 1:</u> 
<u>Equation 2:</u> 
The net equation follows:
As, the net reaction is the result of the addition of first equation and the second equation. So, the equilibrium constant for the net reaction will be the multiplication of first equilibrium constant and the second equilibrium constant.
The value of equilibrium constant for net reaction is:

We are given:


Putting values in above equation, we get:

Hence, the value of
for the net reaction is 
The correct answer is C because a Controlled Experiment tests only one factor at a time and consists of a control group and one or more experimental groups.
Answer: B) KCl
Explanation:
It is an odourless gas with a melting point of of 770°c and a boiling point of about 1420°c, it exists in a white crystalline solid form. KCl is highly water soluble and also soluble in other variety of polar solvent but insoluble in many organic solvents.
Answer: The concentration of unknown sample is 1.8 mg/ml
Explanation:
According to the dilution law,
where,
= concentration of stock solution = ?
= volume of stock solution = 0.25 ml
= concentration of diluted solution = 0.45 mg/ml
= volume of diluted solution = (0.25+0.75) ml = 1.00 ml
Putting in the values we get:
Therefore, concentration of unknown sample is 1.8 mg/ml
Answer : A
0,15 moles of NaOH -------in-------1000ml
x moles of NaOH ---------in-------100ml
x= 0,015 moles of NaOH
final volume =150ml
0,015 moles of NaOH -------in------150ml
x moles of NaOH ------in--------1000ml
x= 0,1 moles of NaOH