Quiz-20 Aldehydes and Ketones

Aldehydes and Ketones Quiz-20

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Q1.  Which of the following statement is correct?

•  Acidity increases with increase in carbon atoms in carboxylic acids.
•  Solubility of carboxylic acid increases with increase in carbon atoms
•  Boiling points of acids are higher than corresponding alcohols
•  None of the above.

Solution
Acidity decreases with increase in number of carbon atoms in carboxylic acid. Solubility of carboxylic acid decrease with increase in number of carbon atoms. Higher acids are insoluble in H_2 O. Boiling points of acids are higher than corresponding alcohols due to greater extent of hydrogen bonding. ∴ (c) is correct answer.

Q2.Acetone and acetaldehyde can be identified by treatment with:

•  NaHSO₃
•  NaCN
•  NaOH+I₂
•  Ag(NH₃ )₂⁺

Solution
All aldehydes give silver mirror with Tollen’s reagent.

Q3.   An aliphatic hydroxy acid is:

•  Maleic acid
•  Mandelic acid
•  Malonic acid
•  Malic acid

Solution

Mandelic acid C₆ H₅5 CHOHCOOH is aromatic hydroxy acid.

Q4. Organic compounds are studied separately from inorganic compounds because:

•  They occur in plants and animals
•  These are combustible and have complex structures
•  These are the compounds of carbon
•  The number of organic compounds is very large

Solution

Q5. The product (A) of the following reaction

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Solution
  The reaction produced as β-lactone do not exist but can only be made by special method

Q6. Complete the following reaction,

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Solution

Q7.The structural formula of the compound isomeric with acetone is:

•  CH_3 CH_2 CHO
•  CH_3 CHO
•  CH_3 CH_2 OH
•  None of these

Solution
Acetone (CH₃ COCH₃) and propanal (CH₃ CH₂ CHO) have same molecular formula C₃ H₆ O and are functional isomers.

Q8.The correct order of increasing acid strength of the compounds

•   B< D< A< C
•   D < A < C< B
•   D < A < B < C
•   A < D < C < B

Solution

-I effect increases acidity. +I effect decreases acidity. -CF₃ exerting more-I effect than Meo- Me₂ CH- exerting more +I effect than –CH₃

Q9.On heating with aqueous alkali, chloroform yields:

•  HCHO
•  HCOOH
•  CH_3 OH
•  CO_2 and H_2 O

Solution:

Q10. Claisen condensation is not given by

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Solution

In Claisen condensation aromatic aldehydes having no α-hydrogen atom react with aldehyde, ketones or esters having α-hydrogen atom in presence of dilute alkali to form α,β-unsaturated carbonyl compound. e.g., 

 As it does not containα-hydrogen atom.