Paper 1 -2020

Question 1

Difference between theoretical and experimental

Answer 1

Contains some covalent character

Question 2

Why enthalpy of hydration becomes less exothermic? From Li+ to K+

Answer 2

Size of ion increases which weakens the attraction between the metal ion and the O- ion in water molecule.

Question 3

Enthalpy of solution

Answer 3

-Lattice form+ lattice hydration
Lattice diss+hydration

Question 4

Similarity and difference between isotopes

Answer 4

Similarity- both have same no. of protons
Difference- different no of neutrons

Question 5

Why it’s necessary to ionise isotopes before they can be analysed?

Answer 5

Ions will be accelerated by electric field
Ions create current before hitting the detector

Question 6

Why atomic radius decreases across period 3?

Answer 6

No. Of protons increases/ Nuc charge increases
Shielding is similar

Question 7

Weak acid meaning

Answer 7

Partially ionises/ dissociates

Question 8

Observation when [x]3+ complex reacts with Na2CO3

Answer 8

Bubbles

Question 9

Aluminium complex add NH4EDTA

Answer 9

[Al(EDTA)]-

Question 10

Why Al3+ complex has PH<7

Answer 10

Greater polarising power due to high charge density which weakens OH bond in water releasing more H+ ions

Question 11

Effect on partial pressure of methanol and on Kp

Answer 11

Increases
No effect

Question 12

Effect of Catalyst on Kp

Answer 12

No effect
Increasesesrate of forward and backwards at equal rates/ Kp only affected by temp

Question 13

XeF4 and PF3 bonding

Answer 13

XeF4 has vdw and PF3 has VDW and dipole dipole . Vdw>dipole dipole stronger img in XeF4 due to larger molecule/ more electrons

Question 14

AgNo3 and NaF observations

Answer 14

Colourless solution

Question 15

Nacl+H2SO4 equation and Obs. Role of H2SO4

Answer 15

2Nacl+H2SO4—> Na2SO4+ 2HCL
Misty/white fumes
Bases/ proton acceptor

Question 16

Redox reaction between NaBr and H2SO4 and explain why it’s redox

Answer 16

2NaBr+ 2H2SO4—> Na2SO4+ Br2+SO2+ 2H2O

Question 17

Cl2 add NaBr ionic equation and observation

Answer 17

Yellow Sol
Cl2+2Br- —>2Cl- +Br2

Question 18

Half eq for negative electrode for C6H12O6

Answer 18

C6H12O+6H20 —>6CO2 +24H+ 24e-

Question 19

Half eq fur +ve electrode

Answer 19

O2+ 4H+4e- —> 2H2O

Question 20

Reaction occurring at Glucose-Oxygen fuel cell

Answer 20

C6H12O6+ 6O2 —> 6CO2+ 6H2O

Question 21

Conventional glucose oxygen fuel cell. -ve electrode has carbon and +ve electrode gas Pt

Answer 21

C| C6H12O6,H+||O2|H+,H2O|Pt

Question 22

What must be done to maintain EMF of fuel cell when in use

Answer 22

Keep conc of reactants constant