1. You didn't post the question to Number 1.
2.
10% means There's 10g in 100ml of this solution.
This is the weight/volume(w/v) expression of concentration.
So
We have Mass =10g
volume =100ml
Molarity = Moles of solute/volume of solution(in LITRES)
Moles=Mass/Molar mass
Molar mass of NaOH=40g/mol
Mole=10/40
=0.25mole
Volume =100ml =0.1Litres
MOLARITY=0.25/0.1 =
=2.5M
OPTION B.
3. NOTE: THE MOLARITY AND NORMALITY OF NAOH AND HCL ARE THE SAME(This doesn't happen for all compounds tho)
So We can take 2.5N(Normality) of NaOH to be 2.5M(Molarity) NaOH
I think you forgot to write the Normality of the second one. I'll take it to be 1N. Maybe you can then Input supposed value when you're solving on your own
So
1N HCl is same as 1M HCL
We were given their respective volumes
2.5M NaOH can also be written as 2.5mole/volume(in Liters)
The volume of NaOH =10ml or 0.01L
Moles = 2.5mole/L x 0.01L
You notice that Liters on top and bottom cancels out... leaving the moles
So
Mole=0.01x2.5 = 0.025moles of NaOH
we're gonna do the same for 1N HCl in 20ml(0.02L)
So
Mole = 1 x 0.02 =0.02moles
Total Mole = 0.02 + 0.025 =0.045moles
The Final Volume is 100ml as stated in the question. It was diluted to 100ml or 0.1L
So
Final Concentration In Molarity
= Total Moles/Volume in L
=0.045/0.1
=0.45M.