Question

By observing the below-given figure which of the options do you think is the correct one?

(a) P1 is greater than P2

(b) P2 is greater than P1

(c) P1 is equal to P2

(d) P1 may be equal to P2

I had been asked this question during an interview.

The doubt is from States of Matter in section States of Matter of Chemistry – Class 11

Answer 1

To answer this question about comparing pressures P1P_1P1​ and P2P_2P2​, the interpretation depends heavily on the given figure and the physical scenario depicted (e.g., a manometer, a gas system, or a fluid dynamics setup). Without the figure, we can generalize based on typical setups:

Possible Scenarios:

1. If the figure shows a U-tube manometer:

   • The liquid levels in the arms of the U-tube indicate the pressure difference.
   • If one side has a higher liquid column, the pressure on that side is lower (hydrostatic pressure principle).

2. If the figure depicts two containers connected with a barrier:

   • Differences in gas pressure could arise from temperature, volume, or other factors.
   • Applying the ideal gas law ($PV=nRT$) can help deduce the pressures.

3. If it is a dynamic fluid system:

   • Bernoulli’s principle may apply, where pressure differences result from velocity changes.

General Observations:

• (a) P1>P2P_1 > P_2P1​>P2​: If P1P_1P1​ corresponds to a higher force exerted or a lower liquid column in a manometer.
• (b) P2>P1P_2 > P_1P2​>P1​: If P2P_2P2​ corresponds to a higher force or a lower liquid column.
• (c) P1=P2P_1 = P_2P1​=P2​: In equilibrium conditions.
• (d) P1P_1P1​ may equal P2P_2P2​: When no specific data is provided about pressure variations.