Question

5. How many u moles will be there in 100 ul of 0.1M of NaCl and CaCl, solution?
A) 100 u moles of NaCl and 200 u B) 100 u moles of NaCl and 100 u moles
moles of CaCl2
of CaCl2
C) 10 u moles of NaCl and 10
р M
moles D) 10 u moles of NaCl and 20 u moles of
of CaCl2
CaCl2​

Answer 1

Given:

Volume of the solution = $100$μl

Molarity of the solution = $0.1M$

To be found:

To calculate the number of μ moles in the solution and to select one correct option from the given four options.

To be recollected:

• Molarity is defined as the ratio of number of moles of solute present in a solution to the total volume of the solution.
• 'μ' is the symbol given to denote '$micro$'. μ moles is the number of

$1$ μ mole = $10^{-6} moles$

Formula to be used:

• The formula for finding the molarity of a solution is given by:

$M=n/V$

where $M=Molarity$

$V$= Volume of the solution

$n$= number of moles

• Using the above formula, the number of moles in the solution is given by:

$n=M*V$....(1)

• In general, this is written for volume in liters, for the calculation of number of moles.
• As per the question, the number of μ moles are required and hence, the volume can be considered directly as μ liters.

Solution:

• As per the given data, molarity of the solution is $0.1M$ and the volume of the given solution is $100$μl.

• From the given data, the number of μ moles in the given solution is calculated using the equation (1).

$n=M*V\\n=0.1*100\\n=10$

Final Answer:

∴Option $C$ is correct. The required number of μ moles in the given solution of $100$μl of $0.1M$ are $10$μ $moles$ of $NaCl$ and $10$μ $moles$ of $CaCl_2$.