A catalyst only has effect on rate of the reaction and is independent of rest all factors including Kc. (A is incorrect)

Kc=[products] / [reactant], when we increase the [ethanol] the equilibrium shifts toward right to oppose the change hence, meanwhile the [ethanol] decreases the [ethyl ethaonate] increase and the value of Kc remains constant as it in dependent to both reactants and products.

Since the reaction is exothermic, when we lower the temperature the reaction shifts to right and product yield increases. Consequently, the value of Kc too increases as Kc is directly proportional to [product]

Raising temperature will shift the value to left and will give low value of Kc. (D is incorrect)

The answer is C.

When the temperature is decreased, the curve shifts toward left with its peak being at higher point. It is because less molecules possess the activation energy. The new curve is drawn on the diagram below:

 

Hence the answer is B

8.

Standard enthalpy change if formation is the enthalpy change when one mole of compound is formed from its elements (elements must be in their standard states)

Carbon is solid in its standard state. (A and B incorrect) and propane is a gas in its standard state. (D is incorrect).

C is the answer.

Simply add the power of all the blocks to get its atomic number. [Rn] has atomic number of 86 (use data booklet). We will get the atomic number 118 (86 + 14 + 10 + 2 + 6). from data booklet, trace the atomic number 118, it will just below Rn which is the zero group.

Answer is D

Ionization energy is inversely proportional to nuclear size of the atom. When there is in addition of other shell (Increase of size) the first ionization decreases enormously. In periodic table the shell increases in group I elements  and ultimately there ionization energy too deacreses.

D is the answer.

Bonds in giant structure are too hard to be broken and hence to dissolve them is utterly impossible.(C is incorrect)

Al2O3 don’t have ionic bond they have covalent bond. (D is incorrect)

Al2O3 is amphoteric in nature; consequently it can react with both acid and base. But note that NaOH is a base and base-base reaction can’t be carried out. (A is incorrect)

So, Al203 acts like a acid and reacts with base to form a aqueous solution of NaAl.

B is the answer.

21.

SN1 reaction is shown by three degree haloalkanes and only C and D are the third degree haloalkanes. (A and B are incorrect)

Among C and D, the latter one gives yellow ppt when reacted with AgNO3 (as D has iodine, Cl turns to white colour when reacted with AgNO3)

D is the answer.

22.

Best yield here means the easiest yield which we can get by reacting the alcohol with SoCl2 as it gives 2-chloropropane is solid and rest all products in gaseous form whereas reaction other reagents gives more than one product in liquid state and it becomes nuisance task to separate the compounds in liquid.

C is the answer.

23.

The products formed are methane, ethene and propene. The fraction of mole ethene formed is 0.5 i.e the mole of ethene formed is double of the mole of methane and propene.

Hence, it can be deduce that  1 mole of methane, 1 mole of propene and 2 mole of ethene is formed.

Hence, C8H18 was the compound.

B is the answer.

25

Aldehydes and ketones are the functional isomers of each other. So they have same molecular formula, empirical formula. (A and B are incorrect)

But the bonding with the functional group and carbon in them is different. So, formula that shows the bond between them can help to distinguish between the compounds, which are structural (shows the bond between carbon-carbon atom and carbon-functional group) and displayed (shows bond between all atoms).

C is the answer.

27.

The reacting compound is halogen-alkane, which reacts with base (NaOH).

During this reaction the NaOH decomposes to form Na+ and OH- ions.

The OH- ion is an nucleophilic and it attacks the Carbon atom which is bonded to the Cl atom (as the carbon contains del + charge) forming a transition state where the carbon atom is bonded to OH and Cl both.

This is the first step of the reaction (the whole reaction is of one step though). In this step, the nucleophilic gets added to the reactant.

Hence it is nucleophilic substitution reaction.

C is the answer.