261.
At $${25^ \circ }C$$ $$molar$$ conductance of $$0.1$$ $$molar$$ aqueous solution of ammonium hydroxide is $$9.54\,\,{\Omega ^{ - 1}}c{m^2}\,mo{l^{ - 1}}$$ and at infinite dilution its molar conductance is $$238\,\,{\Omega ^{ - 1}}\,c{m^2}\,mo{l^{ - 1}}.$$ The degree of ionisation of ammonium hydroxide at the same concentration and temperature is
The salt used to make ‘salt—bridge’ must be such that the ionic mobility of cation and anion are of comparable order so that they can keep the anode and cathode half cells neutral at all times. $$KN{O_3}$$ is used because velocities of $${K^ + }$$ and $$NO_3^ - $$ ions are nearly same
266.
In a Daniell cell,
A
the chemical energy liberated during the redox reaction is converted to electrical energy
B
the electrical energy of the cell is converted to chemical energy
C
the energy of the cell is utilised in conduction of the redox reaction
D
the potential energy of the cell is converted into electrical energy.
Answer :
the chemical energy liberated during the redox reaction is converted to electrical energy
In $${H_2} - {O_2}$$ fuel cell, the combustion of $${H_2}$$ occurs to create potential difference between the two electrodes
268.
In electrolytic reduction of a nitroarene with $$50\% $$ current efficiency $$20.50\,g$$ of the compound is reduced by $$2 \times 96500\,C$$ of electric charge. The molar mass of the compound is
269.
An electric current is passed through silver nitrate solution using silver electrodes. $$15.28\,g$$ of silver was found to be deposited on cathode. What will be
the weight of copper deposited on cathode if same amount of electricity is passed through copper sulphate solution using copper electrodes?
Equivalent $$wt.$$ of $$Ag = \frac{{108}}{1} = 108$$
Equivalent $$wt.$$ of $$Cu = \frac{{63.5}}{2} = 31.75$$
$$\frac{{{\text{Eq}}.\,wt\,{\text{of}}\,\,Ag}}{{{\text{Eq}}.\,wt.\,{\text{of}}\,\,Cu}}$$ $$ = \frac{{{\text{Mass of }}Ag{\text{ deposited}}}}{{{\text{Mass of }}Cu{\text{ deposited}}}}$$
$$\frac{{108}}{{31.75}} = \frac{{15.28}}{W} \Rightarrow W$$ $$ = \frac{{15.28 \times 31.75}}{{108}} = 4.49\,g$$
270.
Electrical conductance through metals is called metallic or electronic conductance and is due to the movement of electrons. The electronic conductance depends on