do you want to overcome that 120 sec barrier for posting doubts??
The best way to approach such a question is to keep in mind the fact that whenever a Period 2 element is involved (from N to F), H bonding is always possible. Next, remember that a highly electronegative element can also form H-bonding. Even Cl can form H bonds but those bonds are not as strong as those of F so we consider HF as our answer.
Answer (c) and (d) both are correct but (d) is most suitable since we do not need the yellow CHI3 compound for our conversion of Butan-2-one to propanoic acid but we need the I- ion to form CHI3- anion and remove the methyl group. NaI generates I- more easily than I2. Hence the given answer is (d)
as x is very small
Since, the oscillation are simple harmonic
If we read the question very carefully, it says when it is expanded to 200 litres at 2 atm pressure. This means that the applied external pressure is 2 atm. So it is written that Pext=2 atm.
It is written constant pressure because the pressure does not change in an isobaric process. This is a case of isobaric process.
The external pressure need change to 2 atm since 2 atm pressure is being applied. We are concerned with the change in internal energy which can be found out by calculating the work done. Work done in an isobaric process depends only on the change in volume and the external pressure applied.