TN 12TH CHEMISTRY - Online Test

Q1. The formation of cyanohydrin from acetone is an example of
Answer : Option D
Explaination / Solution:
No Explaination.


Q2. The method by which aniline cannot be prepared is
Answer : Option B
Explaination / Solution:
No Explaination.


Q3. The correct corresponding order of names of four aldoses with configuration given below Respectively is,
Answer : Option D
Explaination / Solution:
No Explaination.


Q4. Antiseptics and disinfectants either kill or prevent growth of microorganisms. Identify which of the following statement is not true.
Answer : Option A
Explaination / Solution:
No Explaination.


Q5.

Following solutions were prepared by mixing different volumes of NaOH of HCl different concentrations.

i. 60 mL (M/10) HCl + 40mL (M/10) NaOH

ii. 55 mL (M/10) HCl + 45 mL (M/10) NaOH

iii. 75 mL (M/5) HCl + 25mL (M/5) NaOH

iv. 100 mL (M/10) HCl + 100 mL (M/10) NaOH

pH of which one of them will be equal to 1?
Answer : Option D
Explaination / Solution:

iii) 75 ml M/5 HCl + 25ml M/5 NaOH

No of moles of HCl = 0.2×75×10-3 = 15 × 10-3

No of moles of NaOH = 0.2 × 25 × 10-3 = 5 × 10-3

No of moles of HCl after mixing = 15 × 10-3 - 5 × 10-3

= 10 × 10-3

concentration of HCl = No of moles of HCl / Vol in litre

= 10 ×103 / 100 ×103 = 0.1M

for (iii) solution, pH of 0.1M HCl = -log10(0.1)

= 1.


Q6.

Consider the following half cell reactions:

Mn2+ + 2e Mn   Eº = -1.18V

Mn2+ Mn3+ + e-   Eº = -1.51V

The E for the reaction 3Mn2+ Mn+2Mn3+ , and the possibility of the forward reaction are respectively.

Answer : Option B
Explaination / Solution:

Mn2+ + 2e Mn (Eºred) = -1.18V

2[Mn2+ Mn3+ + e- ](Eºox) = −1.51V

3Mn2+ Mn + 2Mn3+        Eºcell?

Eºcell = ( Eºox )+ ( Eºred )

= −1.511.18 and non spontaneous

= −2.69V

Since Eo is –ve ∆G is +ve and the given forward cell reaction is non – spontaneous.


Q7. Which one of the following characteristics are associated with adsorption?
Answer : Option D
Explaination / Solution:

Adsorption leads to decrease in randomness (entropy).i.e. ∆S< 0 for the adsorption to occur, ∆G should be -ve. We know that ∆G=∆H-T∆S if ∆S is -ve, T∆S is +ve. It means that ∆G will become negative only when ∆H is -ve and ∆H>T∆S


Q8.
Answer : Option A
Explaination / Solution:

Hydro boration – Anti markownikoft product i.e., CH3 - CH2 - CH – CH2 – CH2 - OH

Q9. Reaction of acetone with one of the following reagents involves nucleophilic addition followed by elimination of water. The reagent is
Answer : Option C
Explaination / Solution:
No Explaination.


Q10. Which one of the following will not undergo Hofmann bromamide reaction
Answer : Option A
Explaination / Solution:

only primary amides undergo hoffmann bromamide reaction