Resistance and Resistivity

Q.

The specific conductance of a 0.01 M solution of KCl is 0.0014 ohm^-1 cm^-1. Its equivalent conductance is

1. 14

2. 140

3. 1.4

4. 0.14

Q. The specific conductance of $0.01M$ solution of acetic was found to be $0.0163S{m}^{-1}$ at ${25}^{0}C$. Calculate the degree of dissociation of the acid.
Molar conductance of acetic acid at infinite dilution is $390.7\times {10}^{-4}S{m}^{2}mo{l}^{-1}$ at ${25}^{o}C$.

1. 0.34
2. 0.042
3. 0.069
4. 0.182

Q. 3. A potential difference of 20V applied to the ends of a column of M/10 AgNO3 solution, 4cm in diameter and 12 cm in length gave a current of 20 A. What is the molar conductance (cm2ohm-1mol-1) of the solution?

Q. Molar conductivity of a monobasic acid HA having molar concentration equal to $C$ is $\lambda$ and the limiting molar conductivity is ${\lambda }_{\infty }$. The dissociation constant of the acid is

1. $\frac{C\lambda }{{\lambda }_{\infty }-\lambda }$
2. $\frac{C{\lambda }^2}{({\lambda }_{\infty }+\lambda )}$
3. $\frac{C{\lambda }^2}{{\lambda }_{\infty }^2-{\lambda }^2}$
4. $\frac{C{\lambda }^2}{{\lambda }_{\infty }({\lambda }_{\infty }-\lambda )}$

Q.

The unit of conductivity is:

1. ohm^-1

2. ohm^-1 cm^-1

3. cm^-1

4. ohm^-1 cm

Q. 23. What will be the molar conductance lambda if resistivity is x for 0.1 N H2SO4 solution

Q. The resistance of a $0.02N$ solution of an electrolyte $MgC{l}_2$ was found to be $210ohm$ at $298K$ using a conductivity cell with a cell constant of $0.88c{m}^{-1}$. Calculate the equivalent conductivity of the solution.

1. $500oh{m}^{-1}c{m}^{2}e{q}^{-1}$
2. $625oh{m}^{-1}c{m}^{2}e{q}^{-1}$
3. $209.5oh{m}^{-1}c{m}^{2}e{q}^{-1}$
4. $125.5oh{m}^{-1}c{m}^{2}e{q}^{-1}$

Q. The filament resistance of bulb is ......, to its resistance when it is not glowing.

1. greater
2. lower
3. equal
4. none of above.

Q. The resistance of a conductivity cell containing $0.001MKCl$ solution at $298K$ is $1500\Omega$. What is the cell constant if conductivity of $0.001MKCl$ solution at $298K$ is $0.146\times {10}^{-3}Sc{m}^{-1}$.

Q.

Which equation is incorrect?

1. ${\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{NaBr}\right)–{\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{NaCl}\right)={\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{KBr}\right)–{\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{KCl}\right)$

2. ${\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{NaBr}\right)–{\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{NaI}\right)={\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{KBr}\right)–{\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{NaBr}\right)$

3. ${\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{KCl}\right)–{\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{NaCl}\right)={\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{KBr}\right)–{\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{NaBr}\right)$

4. ${\mathrm{\lambda }}_{\mathrm{m}}°\left({\mathrm{H}}_2\mathrm{O}\right)={\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{HCl}\right)+{\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{NaOH}\right)–{\mathrm{\lambda }}_{\mathrm{m}}°\left(\mathrm{NaBr}\right)$

Q. Resistance of a solution (A) is $50ohm$ and that of solution (B) is $100ohm$, both solutions being taken in the same conductivity cell. If equal volumes of solutions (A) and (B) are mixed, what will be the resistance of the mixture, using the same cell? Assume that there is no increase in the degree of dissociation of (A) and (B) on mixing.

Q. The resistance of a $0.02N$ solution of an electrolyte $MgC{l}_2$ was found to be $210ohm$ at $298K$ using a conductivity cell with a cell constant of $0.88c{m}^{-1}$. Calculate the equivalent conductivity of the solution.

1. $625oh{m}^{-1}c{m}^{2}e{q}^{-1}$
2. $500oh{m}^{-1}c{m}^{2}e{q}^{-1}$
3. $125.5oh{m}^{-1}c{m}^{2}e{q}^{-1}$
4. $209.5oh{m}^{-1}c{m}^{2}e{q}^{-1}$

Q.

The inverse of resistance is called:

1. Resistivity

2. Conductance

3. Cell constant

4. Conductivity

Q. Specific conductance of $0.2M$ aqueous solution is $16.4\times {10}^{-2}oh{m}^{-1}c{m}^{-1}$. The molar conductance of solution is

1. $315oh{m}^{-1}c{m}^{2}mo{l}^{-1}$
2. $1201oh{m}^{-1}c{m}^{2}mo{l}^{-1}$
3. $820oh{m}^{-1}c{m}^{2}mo{l}^{-1}$
4. $519oh{m}^{-1}c{m}^{2}mo{l}^{-1}$

Q. Rajat, Sarath and Komal decided to measure resistance of aluminium and took bars of aluminium separately and measured its resistance in same room but got different values of resistance, of same material aluminium. What can be the probable reasons for these variations in resistance for same material?

1. All of the above
2. both length and cross section area of bars were different
3. they took bars of same cross section area but different length.
4. they took bars of same length but different cross section area

Q. The volume occupied by $4.75\text{g}$ of acetylene gas at ${50}^C$ and $750\text{mm Hg}$ pressure is \text{L}\).
(Round off to the nearest integer)
(Given, $R=0.0826{\text{L atm K}}^{-1}{\text{mol}}^{-1}$).

Q. A solution of sodium chloride discharges $6.1\times {10}^{16}N{a}^{+}$ ions and $4.6\times {10}^{16}C{l}^{-}$ ions in 10 seconds. Find the current passing through the solution.

1. 1.7 mA
2. 1.9 mA
3. 1.8 mA
4. 1.6 mA

Q. Specific conductance of $0.1M$ nitric acid is $6.3\times {10}^{-2}oh{m}^{-1}c{m}^{-1}$. The molar conductance of solution is

1. $630oh{m}^{-1}c{m}^{2}mo{l}^{-1}$

2. $315oh{m}^{-1}c{m}^{2}mo{l}^{-1}$

3. $100oh{m}^{-1}c{m}^{2}mo{l}^{-1}$

4. $1201oh{m}^{-1}c{m}^{2}mo{l}^{-1}$

Q. The specific conductance of $0.1N$ $KCl$ solution at ${23}^{o}C$ is $0.012{ohm}^{-1}{cm}^{-1}$. The resistance of cell containing the solution at the same temperature was found to be $55$ ohm. The cell constant will be:

1. $0.142{cm}^{-1}$
2. $0.918{cm}^{-1}$
3. $1.12{cm}^{-1}$
4. $0.66{cm}^{-1}$

Q. A $0.1M$ solution of a monobasic acid has a specific resistance of ‘r’ Ωcm, its molar conductivity is:

1. 10/r
2. 10 r
3. ${10}^4/r$
4. ${10}^4$ r

Q. Resistivity is independent of

1. length of the material
2. Cross section area of the material
3. Nature of the material
4. both (a) and (b)

Q. Column II gives name of material use for device given in column I :

Q. Solution A, B and C of the same strong electrolyte offered resistances of $50\Omega ,100\Omega ,and150\Omega$ in a given conductivity cell. The resistance observed if they are mixed in a volume proportion which is reciprocal of their resistances and tested in the same conductivity cell would be:

1. $67.3\Omega$
2. $81.8\Omega$
3. $100\Omega$
4. $300\Omega$

Q. A wire of length 0.24 m and diameter $3.0\times {10}^{-5}$ m has a resistance of $160\Omega$. Calculate the resistivity of the material.?

1. $4.7\times {10}^{-7}\Omega m$
2. $9.7\times {10}^{-7}\Omega m$
3. $8.7\times {10}^{-7}\Omega m$
4. $6.7\times {10}^{-7}\Omega m$

Q. Assertion :For measuring resistance of an ionic solution, an AC source is used. Reason: Concentration of ionic solution will change if DC source is used.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. A $0.1$ M solution of a monobasic acid has a specific resistance of 'r' ohm-cm. Its molar conductivity is:

1. $\frac{10}{r}$
2. $10r$
3. $\frac{{10}^4}{r}$
4. $\frac{{10}^4}{2r}$

Q.

The unit of equivalent conductivity is

[CPMT 1999; BCECE 2005]

1. 

2. 

3. ohm cm

4. 

Q. Specific conductance of $0.1M$ nitric acid is $6.3\times {10}^{-2}oh{m}^{-1}c{m}^{-1}$. The molar conductance of solution is

1. $630oh{m}^{-1}c{m}^{2}mo{l}^{-1}$

2. $315oh{m}^{-1}c{m}^{2}mo{l}^{-1}$

3. $100oh{m}^{-1}c{m}^{2}mo{l}^{-1}$

4. $1201oh{m}^{-1}c{m}^{2}mo{l}^{-1}$

Q. Which modifications are necessary to determine resistance of solutions by usual method of conductance measurement?

1. A.C. should be used
2. A conductivity cell is used
3. Galvanometer is replaced by headphone or magic eye arrangement
4. None of the above

Q. As the temperature of a conductor increases, its resistivity and conductivity change. The ratio of resistivity to conductivity
(a) increases
(b) decreases
(c) remains constant
(d) may increase or decrease, depending on the actual temperature