In electrolytic refining of nickel (Ni), the anode is Cu-10 atom% Ni and the cathode is pure Ni. Assuming the Cu-Ni solution to be ideal, the absolute value of the minimum voltage (in mv) required for refining is. Given, Faraday's constant = 96490 C mole-1, Temperature = 300 K, R = 8.314 J. mol-1. K-1

An electrolytic refining cell for copper consists of an alloy with activity of copper ac_u = 0.8 as the anode, and pure copper as the cathode. What is the absolute value of the cell potential (in millivolts) at 25°C, given that copper is divalent? Faraday constant is 96500 C/mol and the universal gas constant is 8.314 J/(mol.K).

A

2.9

B

4.6

C

6.8

D

8.9

Choose the right option among the alternatives – A thyristor goes into full conduction in its forward direction when anode/cathode/gate is positive with respect to its anode/cathode/gate and a turn-on voltage or current signal in the form of a pulse is given to its anode/ cathode/gate.

A

Cathode, anode, gate

B

Gate, anode, cathode

C

Anode, cathode, gate

D

Anode, gate, cathode

তড়িৎ রাসায়নিক কোষের emf = ?i. E° Anode(ox) + E°Cathode (Red) 11. E Cathode(Red) - E°Anode (Red) 111. E° Anode(ox) - E°Cathode (Red) নিচের কোনটি সঠিক?

A

i ও ii

B

i ও iii

C

ii ও iii

D

i, ii ও iii

An alloy of nickel and tin has 20 % nickel. Another alloy of nickel and copper has nickel and copper in the ratio 1 ∶ 5. Both the alloys are mixed in the ratio 2 ∶ 5. Quantity of tin is what percent more/less than the quantity of nickel in the final alloy?

A

29.72%

B

25.67%

C

13.45%

D

34.56%

E

13.46%

A 60% spirit solution is mixed with r% spirit solution in the ratio 1 : 3 such that a s% spirit solution is obtained. When a (s/3)% spirit solution is mixed with 55% spirit solution in equal ratio, an (r/2)% spirit solution is obtained. Which of the following can be determined? (A) Value of ‘r’ (B) Value of ‘s’ (C) Volume of the 60% spirit solution mixed initially (D) If 9 liters of r% spirit solution was mixed initially, what was the volume of the s% spirit solution thus obtained?

A

Only C and D

B

Only A and B

C

Only A, C and D

D

Only A, B and D

E

Only A, B and C

A chemical solution appears green when the salt concentration is 8 grams per litre (gpl) and red when it is 10 gpl. Pure water was added to the solution of 1 litre of 15 gpl solution till it turned green. Then 125 ml of the green solution is taken out and x grams of salt is added to the green solution to make it red. Another 500 ml of the final solution was taken out and y litres of green solution is added to get a resultant solution of concentration 9.6 gpl. Assume adding salt doesn’t change its volume and find the ratio of x and y.

A

1

B

1.25

C

1.5

D

2

E

1.75

Assertion (A) For a galvanic cell, oxidation takes place at anode and reduction at cathode.
Reason (R) Electrons in the external circuit move from anode to cathode

A

Both A and R are true and R is the correct explanation of A

B

Both A and R are true, but R is not the correct explanation of A

C

A is true, but R is false

D

A is false, but R is true

An alloy of Nickel and Chromium is to be made such that the alloy comprises of 80% Nickel and 20% Chromium. Mixture A comprises of 60% Nickel and 40% Chromium, while mixture B comprises of 90% Nickel and 10% Chromium. In what ratio should the mixtures be mixed in order to obtain the desired alloy?

A

1 ∶ 1

B

1 ∶ 2

C

2 ∶ 1

D

2 ∶ 2

Which of the following statements are correct for an ideal constant voltage source? 1. Its output voltage remains absolutely constant whatever the change in load current. 2. It possesses zero internal resistance so that internal voltage drop in the source is zero. 3. Output voltage is provided by the source would remain constant irrespective of the amount of current drawn from it. 4. Output voltage provided by the source varies with the amount of current drawn from it.

A

1, 2 and 4 only

B

1, 3 and 4 only

C

2, 3 and 4 only

D

1, 2 and 3 only

Assuming an ideal voltage source, Thevenin's resistance and Thevenin's voltage respectively for the above circuit are

A

15 $$\Omega $$ and 7.5 V

B

20 $$\Omega $$ and 5 V

C

10 $$\Omega $$ and 10 V

D

30 $$\Omega $$ and 15 V

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