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: List what we know.
Stock is $4\,M$ NaOH. We want $350$ ml of $1.2\,M$ NaOH. Find the stock volume needed.

Step 2: Use the dilution rule.
Concentration times volume is conserved, \[ M_1 V_1 = M_2 V_2 \]

Step 3: Plug in.
\[ 4\,V_1 = 1.2 \times 350 = 420 \]

Step 4: Solve.
\[ V_1 = \frac{420}{4} = 105\ \text{ml} \]

Step 5: Answer.
\[ \boxed{105\ \text{ml}} \]