MCQ
There are two identical chambers, completely thermally insulated from surroundings. Both chambers have a partition wall dividing the chambers in two compartments. Compartment $1$ is filled with an ideal gas and Compartment $3$ is filled with a real gas. Compartments $2$ and $4$ are vacuum . A small hole (orifice) is made in the partition walls and the gases are allowed to expand in vacuum

Statement $-1$ : No change in the temperature of the gas takes place when ideal gas expands in vacuum. However, the temperature of real gas goes down (cooling) when it expands in vacuum

Statement $-2$ : The internal energy of an ideal gas is only kinetic. The internal energy of a real gas is kinetic as well as potential

  • Statement $-1$ is false and Statement $-2$ is true
  • B
    Statement $-1$ and Statement $-2$ both are true. Statement $-2$ is the correct explanation of Statement $-1$ 
  • C
    Statement $-1$ is true and Statemcnt $-2$ is false
  • D
    Statement $-1$ and Statement $-2$ both are true. Statement $-2$ is not correct explanation of Statement $- 1$

Answer

Correct option: A.
Statement $-1$ is false and Statement $-2$ is true
a
In ideal gases the molecules are considered as point particles and for point particles, there is no internal excitation, no vibration and no rotation. For an ideal gas the internal energy can only be translational kinetic energy and for real gas both kinetic as well as potential energy

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