Question

Which of the apparatus can be used to introduce more liquid into a reaction and also serve as a pressure valve:
A.stopcock
B.pinchcock
C.thistle tube
D.flask
E.condenser

Answer 1

We need to know that the pressure valve is also known as a relief valve which is used to limit or control the value of pressure which is present in a system. Usually the pressure is created by the process of fire or equipment failure or instrument failure. The liquids are always incompressible due to the increasing pressure and there is a decrease in the distance present between the closely packed molecules.

Complete answer:
The stopcock is connected in the venting position and it always puts when the pressure is in a free state. And it cannot be used to introduce in this case. Hence, option (A) is incorrect.
The pinchcock is used for the regulation of flow of liquid on a flexible tube and it is not used to introduce more liquid into a reaction. Hence, the option (B) is incorrect.
The thistle tube apparatus can be used to introduce more liquid into a reaction and also serve as a pressure valve. And this is used for the addition of small amounts of liquid into an exact position. And this apparatus can be placed through a small hole which is present in the stoppers. Hence, option (C) is correct.
The flask is not used as a material in this case. Hence, the option (D) is incorrect.
The condenser is not used to introduce more liquid into a reaction. Hence, the option (E) is incorrect.

Hence, option (C) is correct.

Note:
We must know that the pressure valve will control the pressure and release the liquid until the pressure reaches its acceptable level. And these are mainly used in the operations like petrochemicals, power generation in the term of steam, oil and gas. And it has so many applications in chemical processes and in refining areas. And if any damage is caused to the pressure valve, there will be a bleed of the oil.