The number of moles of NaOH present in 10 litres of 1 molar solution is:

10

The correct answer is option 1. 10.

Given:

Molarity of the solution (\( \text{M} \)) = 1 Molar (1 mol/L)

Volume of the solution = 10 liters

To find the number of moles of NaOH present in the solution, we use the formula for calculating moles from molarity and volume:

\(\text{Number of moles} = \text{Molarity} \times \text{Volume in liters}\)

Substitute the given values into the formula:

\(\text{Number of moles} = 1 \, \text{mol/L} \times 10 \, \text{L}\)

Now, perform the multiplication:

\(\text{Number of moles} = 10 \, \text{moles} \)

Therefore, there are 10 moles of NaOH present in the solution. This calculation shows that molarity (moles per liter) multiplied by volume in liters gives us the total number of moles of the substance in the solution. In this case, \( 1 \, \text{mol/L} \) (molarity) multiplied by \( 10 \, \text{L} \) (volume) equals \( 10 \, \text{moles} \) of NaOH.

So, the correct answer remains 10.