I thinlk it's by radiation?......
We know that to relate solutions of with the factors of molarity and volume, we can use the equation:

**
NOTE: The volume as indicated in this question is defined in L, not mL, so that conversion must be made. However it is 1000 mL = 1 L.
So now we can assign values to these variables. Let us say that the 18 M

is the left side of the equation. Then we have:

We can then solve for

:

and

or

We now know that the total amount of volume of the 4.35 M solution will be
210 mL. This is assuming that the entirety of the 50 mL of 18 M is used and the rest (160 mL) of water is then added.
Answer: The molecular formula will be 
Explanation:
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mass of C = 40.0 g
Mass of O = 53.3 g
Mass of H = 6.66 g
Step 1 : convert given masses into moles.
Moles of C =
Moles of O =
Moles of H =
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C =
For O =
For H = 
The ratio of C : O : H = 1: 1: 2
Hence the empirical formula is
The empirical weight of
= 1(12)+1(16)+2(1)= 30g.
The molecular weight = 60 g/mole
Now we have to calculate the molecular formula.
The molecular formula will be=