Hello~ I think I can help you out with these questions.
Q.6. Which gas least resembles ideal gas? To answer this question I think you need to recall the kinetic theory of gases and one of them will be "No intermolecular forces between gas molecules."
(a) Ammonia(try to draw the structure) is capable of forming hydrogen bond. Requirement to form H-bond: 1.) F,O or N atom contains lone pairs 2.)F,O or N is covalently bonded to H atom. And since ammonia fulfills all the requirements here, Ammonia is capable of forming one of the strongest intermolecular forces which is H-bond.
(b)Helium is a noble gas which is unreactive(Does not form any bonds with other gas molecules) so this makes it behave more like ideal gas.
(c)H2 gas are held together by weak V.D.W forces only.
(d)Trichloromethane contains permanently induced dipole-dipole between the C-Cl due to the presence of the electronegative atom Cl. However, this intermolecular force is still weaker than H-bond.
So the most attractive force can be found in Ammonia so the answer will be A.
Q.21. Chiral centres: When a carbon atom is covalently bonded to 4 different groups. So any carbon bonded to double bonds should be ignored. And here, we must consider the benzene ring as one group. Do not attempt to find chiral centres from the benzene ring. And the final answer that I obtained is 1 chiral centre which is B.
Q.33. (1) This is correct because when the activation energy is too high, more energy need to be supplied in order for the reaction to occur so high activation energy may be one of the reason why hydrazine does not react well with oxygen.
(2) Hydrazine only involved N=N and not N triple bonds. So this is not a right choice.
(3) Being a liquid does not determines how good or bad a reaction is. Example: Alcohol is a liquid and you can react alcohol with oxygen(Process is known as combustion). So 3 is not a wise choice either.
You have only one correct answer here so it's D.
Hope it helps
Your explanations were very helpful.
Thanks
I have a small doubt regarding intermolecular forces and about 31 qs.
*Generally between which types of molecules are van der waal's forces made, and between which type of molecules are permanently induced dipole-dipole made?I am a bit confused.
*And in 31 qs I think that a triple bond is present between N atoms as in my diagram.
In the examiner's report it said,
Question 33 explored the fact that hydrazine does not burn spontaneously in oxygen. 28% of candidates correctly appreciated that this is a mark of high activation energy and gave the key D, but 40% gave B as the key, incorporating the high strength of the N≡N triple bond as being a factor. This would be relevant to a calculation of the overall change in enthalpy, but not to the rate of the reaction.
But I didn't understand the last statement.
Do you know what it means?