Chemistry mixed mcq 1

Aldol condensation between two compounds followed by dehydration gives methyl vinyl ketone. Then, the compounds are

• HCHO and CH₃COCH₃

  
  

• HCHO and CH₃ CHO

• two molecules of

  CH₃ CHO

• two molecules of CH₃COCH₃.

Answer explanation

HCHO + CH₃COCH₃

— > HOH₂CCH₂COCH₃→ H₂C=CHCOCH₃

Methyl-vinyl ketone

The order of reactivities of the following alkyl halides for an Sn2 reaction is

• RF > RCl > RBr > RI

• RF > RBr > RCI > RI

• RCl > RBr > RF > RI

• RI > RBr > RCI > RF

Answer explanation

The replacement of halide group follows the order

I^->Br^->Cl^->F^-

This reactivity order has been explained on the basis of

greater bond length (maximum for C - I) which lowers the

bad energy and makes the molecule less stable.

The ionic conductance depends on

• the nature of the electrolyte

• the size of the ions produced

• change in temperature

• all of these.

Match the column-I with column-II and mark the appropriate choice.

• (a) (A) → (iv), (B) → (ii), (C) → (iii), (D) → (i)

• (b) (A) → (ii), (B) → (iii), (C) → (i), (D) → (iv)

• (c) (A) → (iii), (B) → (iv), (C) → (ii), (D) → (i)

• (d) (A) → (i), (B) → (iii), (C) → (iv), (D) → (ii)

The empirical formula of a non-electrolyte is CH₂O. A solution containing 6 g of the compound exerts the of the compound is

same osmotic pressure as that of 0.05 M glucose solution at the same temperature. The molecular formula

• C₂H₄O₂

• C₃H₆O₃

• C₅H₁₀O₅

• C₄H₈O₄

Answer explanation

Which of the following tests/ reactions is given by aldehydes as well as ketones?

• Fehling's test

• Tollens' test

• 2,4-DNP test

  
  

• Cannizzaro reaction

Answer explanation

2,4 DNP test is given both aldehydes and ketones. whereas Fehlings's, Cannizzaro, Tollen's reaction is shown by aldehydes only

The product (B) of the following reaction is

• 
• 
• 
• CH₄

Answer explanation

Which factor has no influence on the rate of reaction?

• Molecularity

• Temperature

• Concentration of reactant

• Nature of reactant

Answer explanation

The number of reacting species (atoms, ions or molecules taking part in an elementary reaction is called molecularity and it has no influence on the rate of reaction.

Which of the following amines will give carbylamine reaction?

• (C₂H₅)₃N

• (C₂H₅)₂NH

• C₂H₅NH₂

  _Explanation

  Only primary amines will give carbylamine

• C₃H₇NHC₂H₅

What will be the freezing point of a 0.5 m KCl solution? The molal freezing point constant of water is

1.86° Cm^-1

• - 1.86°C

• -0.372°C

• -3.2°C

• 0°C

Answer explanation