Q. No.A standard aqueous solution of a weak acid HX has a pH of 5 and shows a conductance of 4×10–5 S when placed in a conductivity cell with electrode separation of 15 cm and cross-sectional area of 1 cm².
Assuming that the degree of dissociation of HX is very small, calculate the limiting molar conductivity of the solution (in Sm2mol-1).
1. Three (3)2. Five (5)
3. Six (6)
4. Seven (7)
Subtopic: Conductance & Conductivity |
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0.18 M HQ solution has molar conductivity \(\frac { 1 } {30}\) times the molar conductivity of 0.02 M HZ solution. Find the value of \(pK_a (HQ)-pK_a(HZ)\), given that \(\alpha\) is very less than 1.
Assume that \(\lambda_{\mathrm{m}}^{\infty}\left(\mathrm{Q}^{-}\right)=\lambda_{\mathrm{m}}^{\infty}\left(\mathrm{Z}^{-}\right) \):
1. 2
2. 0
3. 4
4. 8
Assume that \(\lambda_{\mathrm{m}}^{\infty}\left(\mathrm{Q}^{-}\right)=\lambda_{\mathrm{m}}^{\infty}\left(\mathrm{Z}^{-}\right) \):
1. 2
2. 0
3. 4
4. 8
Subtopic: Conductance & Conductivity |
Level 3: 35%-60%
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What is the order of limiting molar conductivity for the given cations in water at \(298~K\) ?
\(\mathrm{H^+, Na^+, K^+, Ca^{2+}, Mg^{2+}}\)
1. \(\mathrm{H}^{+}>\mathrm{K}^{+}>\mathrm{Na}^{+}>\mathrm{Ca}^{2+}>\mathrm{Mg}^{2+}\)
2. \(\mathrm{H}^{+}>\mathrm{Na}^{+}<\mathrm{K}^{+}>\mathrm{Ca}^{2+}>\mathrm{Mg}^{2+} \)
3. \(\mathrm{Na}^{+}>\mathrm{K}^{+}>\mathrm{H}^{+}>\mathrm{Ca}^{2+}>\mathrm{Mg}^{2+}\)
4. \(\mathrm{H}^{+}>\mathrm{K}^{+}>\mathrm{Ca}^{2+}>\mathrm{Na}^{+}>\mathrm{Mg}^{2+} \)
\(\mathrm{H^+, Na^+, K^+, Ca^{2+}, Mg^{2+}}\)
1. \(\mathrm{H}^{+}>\mathrm{K}^{+}>\mathrm{Na}^{+}>\mathrm{Ca}^{2+}>\mathrm{Mg}^{2+}\)
2. \(\mathrm{H}^{+}>\mathrm{Na}^{+}<\mathrm{K}^{+}>\mathrm{Ca}^{2+}>\mathrm{Mg}^{2+} \)
3. \(\mathrm{Na}^{+}>\mathrm{K}^{+}>\mathrm{H}^{+}>\mathrm{Ca}^{2+}>\mathrm{Mg}^{2+}\)
4. \(\mathrm{H}^{+}>\mathrm{K}^{+}>\mathrm{Ca}^{2+}>\mathrm{Na}^{+}>\mathrm{Mg}^{2+} \)
Subtopic: Conductance & Conductivity |
Level 3: 35%-60%
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The limiting molar conductivities of a divalent cation \(\left(\mathrm{M}^{2+}\right)~\)and a monovalent anion \(\left(\mathrm{A}^{-}\right)~\)are \(57 \mathrm{~S} \mathrm{~cm}^2\) \( \mathrm{mol}^{-1}\) and \(73 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}\) respectively. What is the limiting molar conductivity of their compound in \(\mathrm{S}~ \mathrm{cm}^2 \mathrm{~mol}^{-1}\)?
1. 203
2. 421
3. 143
4. 303
1. 203
2. 421
3. 143
4. 303
Subtopic: Conductance & Conductivity |
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Which of the following represents correct unit of slope of graph between molar conductivity \((\wedge \mathrm{m})\) and \((\text {conc})^{1 / 2}\)?
| 1. | \( \mathrm{S} \mathrm{cm}^{1 / 2} \mathrm{~mol}^{-1 / 2}\) | 2. | \(\mathrm{S} \mathrm{cm}^{3 / 2} \mathrm{~mol}^{-2}\) |
| 3. | \(\mathrm{S} \mathrm{cm}^{7 / 2} \mathrm{~mol}^{-3 / 2}\) | 4. | \(\mathrm{S} \mathrm{cm}^{5 / 2} \mathrm{~mol}^{-3 / 2}\) |
Subtopic: Conductance & Conductivity |
Level 3: 35%-60%
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The graph represents the variation of molar conductance (\(\Lambda_m\)) with the square root of concentration (\(\sqrt{C}\)) for two electrolytes, 'A' and 'B'. Based on the graph, the nature of both electrolytes is:
1. A → Strong Electrolyte, B→ Strong Electrolyte
2. A → Weak Electrolyte, B → Strong Electrolyte
3. A → Strong Electrolyte, B → Weak Electrolyte
4. A → Weak electrolyte, B → Weak Electrolyte
1. A → Strong Electrolyte, B→ Strong Electrolyte
2. A → Weak Electrolyte, B → Strong Electrolyte
3. A → Strong Electrolyte, B → Weak Electrolyte
4. A → Weak electrolyte, B → Weak Electrolyte
Subtopic: Conductance & Conductivity |
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Which of the following is correct for strong electrolyte (B > 0)?
1. \(\lambda_m-\lambda_m^0-B \sqrt{C}=0 \)
2. \(\lambda_m+\lambda_m^0-B \sqrt{C}=0 \)
3. \( \lambda_m-\lambda_m^0+B \sqrt{C}=0\)
4. \( \lambda_m+\lambda_m^0+B \sqrt{C}=0\)
1. \(\lambda_m-\lambda_m^0-B \sqrt{C}=0 \)
2. \(\lambda_m+\lambda_m^0-B \sqrt{C}=0 \)
3. \( \lambda_m-\lambda_m^0+B \sqrt{C}=0\)
4. \( \lambda_m+\lambda_m^0+B \sqrt{C}=0\)
Subtopic: Conductance & Conductivity |
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The resistivity of a 0.8 M solution of an electrolyte is 5×10−3 Ω cm. If λm is 2.5×10x,
the value of x is:
1. 4
2. 8
3. 5
4. 9
the value of x is:
1. 4
2. 8
3. 5
4. 9
Subtopic: Conductance & Conductivity |
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For a given cell, a 0.1 molar solution has a resistance of \(20 \ \Omega\) and molar conductivity of \(0.154 \times 10^{-3} S~cm^2~mol^{-1} \).
The value of the cell constant is:
The value of the cell constant is:
| 1. | \(3.08 \times 10^{-7} cm^{-1}\) | 2. | \(30.8 \times 10^{-7} cm^{-1}\) |
| 3. | \(0.308 \times 10^{-9} cm^{-1}\) | 4. | \(4.08 \times 10^{-6} cm^{-1}\) |
Subtopic: Conductance & Conductivity |
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Determine the cell constant of a conductivity cell containing a 0.01 M KCl solution at 298 K. The given data includes a resistance of 1750 Ω and a conductivity of 0.152×10−3 S cm−1.
| 1. | \(266 \times 10^{-3} \mathrm{~m}^{-1}\) | 2. | \(166 \times 10^{-3} \mathrm{~cm}^{-1}\) |
| 3. | \(266 \times 10^{-3} \mathrm{~cm}^{-1}\) | 4. | \(166 \times 10^{-3} \mathrm{~m}^{-1}\) |
Subtopic: Conductance & Conductivity | Kohlrausch Law & Cell Constant |
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