Advertisements
Advertisements
Question
Calculate molar conductivities at zero concentration for CaCl2 and NaCl.
Given: molar ionic conductivities of Ca2+, Cl–, Na+ ions are respectively, 104, 76.4, 50.1 Ω–1 cm–2 mol–1
Solution
Given:
`lambda_("Ca"^(2+))^0` = 104 Ω–1 cm2 mol–1,
`lambda_("Cl"^(-))^0` = 76.4 Ω–1 cm2 mol–1,
`lambda_("Na"^(+))^0` = 50.1 Ω–1 cm2 mol–1,
To find: Molar conductivity at zero concentration for CaCl2 and NaCl:
∧0 (CaCl2) and ∧0 (NaCl)
Formula: ∧0 = `"n"_+ lambda_+^0 + "n"_(-)lambda_(-)^0`
Calculation: According to Kohlrausch law,
∧0(CaCl2) = `lambda_("Ca"^(2+))^0` + `2lambda_("Cl"^(-))^0`
= 104 Ω–1 cm2 mol–1 + 2 × 76.4 Ω–1 cm2 mol–1
= 256.8 Ω–1 cm2 mol–1
∧0(NaCl) = `lambda_("Na"^(+))^0` + `lambda_("Cl"^(-))^0`
= 50.1 Ω–1 cm2 mol–1 + 76.4 Ω–1 cm2 mol–1
= 126.5 Ω–1 cm2 mol–1
Molar conductivity at zero concentration of CaCl2 is 256.8 Ω–1 cm2 mol–1
Molar conductivity at zero concentration of NaCl is 126.5 Ω–1 cm2 mol–1
APPEARS IN
RELATED QUESTIONS
0.05 M NaOH solution offered a resistance of 31.6 Ω in a conductivity cell at 298 K. If the cell constant of the cell is 0.367 cm-1, calculate the molar conductivity of NaOH solution.
What is a cell constant? What are its units? How is it determined experimentally?
Answer the following in one or two sentences.
Write the relationship between conductivity and molar conductivity and hence unit of molar conductivity.
Answer the following:
What is Kohlrausch law of independent migration of ions? How is it useful in obtaining molar conductivity at zero concentration of a weak electrolyte? Explain with an example.
State Kohlrausch law of independent migration of ions.
Write three important steps required to determine molar conductivity.
Molar conductance of BaCl2, H2SO4 and HCl at infinite dilution are X1, X2 and X3 respectively. Molar conductance of BaSO4 at infinite dilution is ____________.
The CORRECT unit of molar conductivity is ____________.
For the reaction \[\ce{A -> B}\], the rate increases by a factor of 2.25 when the concentration of A is increased by 1.5. What is the order of the reaction?
The resistance of `1/10`M solution is 2.5 × 103 ohm. What is the molar conductivity of solution? (cell constant = 1.25 cm-1).
Conductivity of KCI solution is 0.0027 Ω−1 m−1 at 25°C. The resistance of the solution is 82.4 Ω. The cell constant is ____________ m−1.
The molar conductivities at zero concentration for Ca2+ and CaCl2 are 104 and 256.8 Ω−1 cm2 mol−1 respectively. The molar conductivity at zero concentration for Cl− is ____________.
The SI unit of resistivity and molar conductivity are respectively ____________.
The resistance of a conductivity cell containing 0.001 M KCl solution at 298 K is 1500 Ω. What is the cell constant if conductivity of 0.001 M KCI solution at 298 K is 0.146 × 10−3 S cm−1?
In 2 hours, a certain current liberates 0.504 g hydrogen. How many grams of copper can be deposited by the same current flowing for the same time in a CuSO4 solution?
(Molar mass of Cu = 63.5 g mol−1, H2 = 2.0 g mol−1)
Which of the following graph represents the variation of `∧` with `sqrt"c"` for acetic acid solution?
What is the cell constant of `"N"/10 "KCl"` solution at 25°C, if conductivity and resistance of a solution is 0.0112 Ω−1 cm−1 and 55.0 Ω respectively?
What is the relation between cell constant, conductivity and electrical resistance?
What is the value of cell constant if conductance and conductivity of a solution is same?
What is the unit of electrical conductance?
What is the conductivity of 0.01 M NaCl solution if resistance and cell constant of NaCl solution are 375 ohms and 0.5 cm-1 respectively at 298 K?
A conductivity cell dipped in 0.5 M KCl gives a resistance of 250 ohms. If the conductivity of KC I solution is 6.68 × 10-3 S cm-1, what is the cell constant?
The value of [H3O+] in mol lit–1 of 0.001 M acetic acid solution (Ka = 1.8 × 10–5) is ______.
Specific conductance of 0.1 M sodium chloride solution is 1.06 × 10−2 ohm−1 cm−1. Its molar conductance in ohm−1 cm2 mol−1 is ______.
A conductivity cell filled with 0.02 M AgNO3 gives at 25°C resistance of 947 ohms. If the cell constant is 2.3 cm-1, what is the molar conductivity of 0.02 M AgNO3 at 25°C?
Write the relation between molar conductivity and molar ionic conductivities for the electrolytes:
- Na2SO4
- AlCl3
