Question

(ii) SCN solution. You are provided with a 0.5 M solution. Calculate the volume of solution required to give final SCN concentrations of: Final (SCN) 0.01 0.05 0.10 0.20 0.30 0.40 Volume 0.5 M solution needed For this type of calculation always work from the number of moles of SCN required. (iii) Sufficient 3 M HNO3 to make the final solution 0.2 M with respect to HNO3. The volume of HNO3 required is — _ml.

Answer 1

Let we are preparing of 100 ml solution of each. So there is a simple formula for this

M1 * V1 = M2 * V2

(Soln 1) (soln 2)

We di Arrent [SCNO] = 0.5m . Let we prepared 100 mi 2017. i Final (SONT = 0.01 m By formula mivi = m2 V₂ (0.5m) Courm) 0.5X 4 = 0.01 X 100 1 V = oroix too 0.50 v=ami I So 0.5 m to we make need o.olm 2m1 Soln forum of 0.5m . Final (SCN) = 0.05 Tmv, - m₂ V₂ 1 = 0.5X V Vi= 0.05% 100 00 5x1002 050 V, - lom! So we need 10 ml of 0.5m Bur) in Final (sen) = 0.10 mivo = m₂ V2 0.5X = 0 lox 100 Vi= ollo X1002 0.50 IV.20m So we need 20 ml g 0.5(SCH)

# Final ISCHI = 0.20 mv, = M₂ V2 0-5x v, 0.20 X 100 so we need 40m1 g 0.5ml SCN 05 1 y, 40m Final (SCN) = 0.30 miy = M2 V2 out 0 5x V, = 0-30 X 100 so we need g 0.5m Gom/ (SCN) V = 60ml Final SON'] = 0.40 my = m2 V₂ need som 0.5XY, = 0.40XV0o g 0.5m (SCH ] 400 o's Ni= somil giren 3x (HHO3) = 3m mv = m2 V₂ (3m) (62m) = 0.2X 100 = 206.66 T= 6.67 mil 6.67m1 of 3m 3 So He need HNO3 to prepare 0.2m HHOZ