Question

The volume of \(4M\) NaOH (in ml) required to make \(350\) ml solution of \(1.2M\) NaOH is _ _ _. (in integer)

Hint:

For dilution problems always use: \[ M_1V_1=M_2V_2 \] where concentration multiplied by volume remains constant.

Answer 1

Correct Answer: 105

Step 1: Write the given data.
Initial concentration of NaOH solution:
\[ M_1=4M \] Final concentration required:
\[ M_2=1.2M \] Final volume required:
\[ V_2=350\ \text{ml} \]

Step 2: Recall dilution formula.
For dilution of solutions,
\[ M_1V_1=M_2V_2 \] where \(V_1\) is the volume of stock solution required.

Step 3: Substitute the values.
\[ 4\times V_1=1.2\times 350 \]

Step 4: Simplify the right-hand side.
\[ 1.2\times 350=420 \] Thus,
\[ 4V_1=420 \]

Step 5: Solve for \(V_1\).
\[ V_1=\frac{420}{4} \] \[ V_1=105 \]

Step 6: Write the required volume.
Therefore, the volume of \(4M\) NaOH required is
\[ 105\ \text{ml} \]

Step 7: Final conclusion.
Hence, the required volume is
\[ \boxed{105} \]