Solution :
Molecular mass of NaOH is 23 g/mol .
So, number of moles of NaOH is given by :
[tex]n = \dfrac{10}{40}\ mole[/tex]
Now, we know molarity is given by :
[tex]Molarity = \dfrac{Number \ of \ moles\ of \ salute}{Volume ( in \ Liter ) }[/tex]
[tex]M = \dfrac{10}{40\times 2.4} \ M\\\\M = 0.104 \ M[/tex]
Hence, this is the required solution.