How to do this question plz answer Using a 500cm3 flask what mass of pure NaOH do we add to make a 0.2 moles solution?​

Explanation:

This is a pretty simple question of mole concept and the solution goes like this:

Given:

Volume of NaOH = 500 mL

Molarity of the aqueous solution = 0.5 M

Molar mass of NaOH= (23+16+1)g = 40g

Let the mass of NaOH be x.

Now , according to formula number of moles of a given substance = given mass/molar mass

Therefore, no. Of moles of NaOH= x/40

Since, molarity = number of moles of solute/ volume of solution in lit.

Hence, 0.5 = (x/40)/(500/1000)

Solving this we get x= 10g

Hence, 10g of NaOH should be taken to obtain a 0.5 M solution of volume 500 mL.

I hope I could explain the numerical well and help you.

if you're asking what comes out, it's steam.

i think it's letter a.