help@askiitians.com

+91-87964 74404

Grade upto college level Physical Chemistry

Upon mixing 45.0 ml. of 0.25 M lead nitrate solution with 25.0 ml of 0.10 M chromic sulphate solution, precipitation of lead sulphate takes place. How many moles of lead sulphate are formed? Also, calculate the molar concentrations of the species left behind in the final solution. Assume that lead sulphate is completely insoluble.

Amit Saxena

12 Years agoGrade upto college level

1 Answer

Navjyot Kalra

12 Years ago

Calculation of number of moles in 45 ml. of 0.025 M Pb(NO₃)₂

Moles of Pb(NO₃)₂ = 0.25 * 45/1000 = 0.01125

∴ Initital moles of Pb²⁺ = 0.01125

Moles of $NO_{3}^{-}$ = 0.01125 * 2 = 0.02250 [1 mole Pb(NO₃)₂ ≡ 2 moles of NO₃]

Calculation of number of moles in 25 ml. of 0.1 M chromic sulphate

Moles of chromic sulphate (Cr₂(SO₄)₃ = 0.1 * 25/1000 = 0.0025 moles.

Moles of $SO_{4}^{-}$ = 0.0025 * 3 = 0.0075 [1 Mole of chromic sulphate ≡ 3 moles of SO₄^2-]

Moles of PbSO₄ formed = 0.0075 [SO₄^2- is totally consumed]

Moles of Pb²⁺ left = 0.01125 – 0.0075 = 0.00375

Moles of $NO_{3}^{-}$ left = 0.02250 [NO₃^- remain untreated]

Moles of chromium ions = 0.0025 * 2 = 0.005

Total volume of the solution = 45 + 25 = 70 ml.

∴ Molar concentration of the species left

(i) Pb²⁺ = 0.00375/70 * 1000 = 0.05357 M

(ii) $NO_{3}^{-}$ = 0.0225/70 * 1000 = 0.3214 M

(iii) Cr³⁺ = 0.005/70 * 1000 = 0.0714 M

Which of the following aqueous solutions remains neutral after
electrolysis

physical chemistry

0 Answer Available

Last Activity: 3 Years ago

In the reaction A + 2B ⇌ 2C, if 2 moles of A, 3 moles of B and 2 moles of C are placed in a 2 L flask and
the equilibrium concentration of C is 0.5 mol/L. The equilibrium constant (KC) for the reaction is.....and please tell how you know that the reaction is going forward .. imean how to calculate the reaction quotient ???

physical chemistry

1 Answer Available

Last Activity: 3 Years ago

True or false when an electron in ground state of hydrogen atom is excited with an energy that is greayer than e2-e1 but less than e3-e1 the electron will get excited n=2

physical chemistry

1 Answer Available

Last Activity: 3 Years ago

18 19 gram mixture of na2co3 and nahco3 on heating gives 2.2 gram CO2 gas find the percent nahco3 (by mass) in mixture

physical chemistry

1 Answer Available

Last Activity: 4 Years ago

A 100 cm cube solution of sodium carbonate is prepared by dissolving 8.653 g of salt in water the density of solution is 1.0816g per ml what are the molarity and molality of the solution.

physical chemistry

1 Answer Available

Last Activity: 4 Years ago

View all Questions