How many moles of MgCl2, are in 400. L of a 0.021 M solution? A 0.75 mol
B 8.4 mol
C 7.5 mol
D 0.84 mol

The correct answer to the following question will be Option B "8.4 mol".

Explanation:

The given values are:

Molarity of a solution = 0.021 M

Litres of solution = 400 L

Let the moles be "x".

As we know,

⇒  

On putting the estimated values, we get

⇒  

On applying cross-multiplication, we get

⇒  

⇒  

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.

all eukaryotic cell have mitochondria : )