How much water should be added to `2M HCl` solution to form `1"litre"` of `0.5M HCl` ? .

Explanation

To solve the problem of how much water should be added to a 2M HCl solution to form 1 liter of 0.5M HCl, we can follow these steps:

### Step 1: Use the dilution formula
We will use the dilution formula, which is given by:
\[ M_1 V_1 = M_2 V_2 \]
where:
- \( M_1 \) = initial molarity (2M)
- \( V_1 \) = volume of the initial solution (unknown)
...