Tag: electrochemistry

Questions Related to electrochemistry

A compass placed in an electric field will be deflected due to:

  1. heating effect of current

  2. magnetic effect of current

  3. conducting effect

  4. resistance of the needle to the electric field


Correct Option: B
Explanation:

An electric current causes a magnetic field around it just like a magnet causes a magnetic field. When you moved the compass near an electric field, the magnetic field produced due to the electric field deflects the compass.


Hence, the correct option is $\text{B}$

Which of the following is a good conductor of electricity?

  1. Tap water

  2. Distilled water

  3. Sea water

  4. Rain water


Correct Option: A,C,D
Explanation:
Sea water, tap water, and rainwater comprise of salt and many other impurities whereas distilled is void of such impurities. 

Those impurities, act as ions and help in the transfer of charge.
 
Hence, they are good conductor of electricity.

Distilled water is highly purified water that does not contain any salts. Hence, it do not conduct electricity.

Therefore, option A, C and D are correct.

Which of the following does not conduct electricity ?

  1. Molten NaoH

  2. Molten KOH

  3. Solid NaCI

  4. Aqueous NaCI


Correct Option: C

A Coordinates complex has the formula $PtCl.2KCl$. Electrical conductance measurements indicate the pressure of three ion in one formulaa unit. Treatment with $AgNO _{3}$ produces no precipiate of $AgCl$. What is the coordinates no of $Pt$ this complex?

  1. $6$

  2. $5$

  3. $4$

  4. $3$


Correct Option: B

An acidic solution of Cu+ salt containing 0.4 g of Cu+ is electrolysed until all the Cu is deposited. The electrolysis is continued for 7 more minutes with volume of the solution kept at 100 ml and the current at 1.2 amp. Calculate volume of the gases evolved at NTP during entire electrolysis( atomic weight of Cu= 63.6)

  1. H2 = 68.32 ; O2 = 85.23 ml

  2. H2 = 40.34 ; O2 =70.12 ml

  3. H2= 51.46 ; O2 = 90.12 ml

  4. H2=58.46 ; O2 = 99.68 ml


Correct Option: D

An electrolytic cell was set up. Distilled water is placed in the cell and battery is switched on. The bulb is also connected through a battery. The bulb will:

  1. glow

  2. not glow

  3. partially glow

  4. none of the above


Correct Option: B
Explanation:

Distilled water is a bad conductor of electricity. It do not contains any impurities to carry the current. So the circuit will not be completed for the bulb to glow.

Which of the following is a good conductor of electricity?

  1. $HCOOH$

  2. $CH _3Cl$

  3. $C _2H _5OH$

  4. $KOH$


Correct Option: D
Explanation:

KOH being a strong base is a good conductor of electricity. 

Given below are the half cell reactions

${ Mn }^{ 2+ }+{ 2e }^{ - }\longrightarrow { Mn }  E=-1.81V$

$2\left( { Mn }^{ 3+ }+{ e }^{ - }\longrightarrow { Mn }^{ 2+ } \right) E=+1.51V$ will be

        




  1. 0.33V ; the reaction will not occur .

  2. 0.33V ; the reaction will occur.

  3. 2.69V ; the reaction will not occur.

  4. 2.69V ; the reaction will occur


Correct Option: A

Which technique should be used to determine if a solution contains a molecular or ionic solute?

  1. Conductivity

  2. Calorimetry

  3. Precipitation

  4. Spectophotometry


Correct Option: A
Explanation:

The presence of ionic solute in a solution can be determined by measuring its conductivity because ions are good conductor of electricity.

The first step in the extraction of Cu from copper pyrites is?

  1. Reduction by carbon

  2. Electrolysis of ore

  3. A Roasting of ore in $O _2$

  4. Magnetic separation


Correct Option: B