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Answer the following.
Write the product(s) of the following reactions: (1) (2) (3) Give one chemical test each to…
(i)[3.0]
Write the product(s) of the following reactions:
(1) $\text{CH}_3\text{COCH}_3 + \text{H}_2\text{NOH} \rightarrow$
(2) $2\text{ C}_6\text{H}_5\text{CHO} + \text{conc. NaOH} \rightarrow$
(3) $\text{CH}_3\text{COOH} \xrightarrow{\text{Cl}_2/\text{P}}$
(ii)[2.0]
Give one chemical test each to distinguish between the following pairs of compounds:
(1) Benzaldehyde and Benzoic acid
(2) Propanal and Propanone
Answer
Answer (i)
AIEquations: $\mathrm{CH_{3}COCH_{3}} + \mathrm{NH_{2}OH} \longrightarrow \mathrm{(CH_{3})_{2}C=NOH} + \mathrm{H_{2}O}$ $2\mathrm{C_{6}H_{5}CHO} + \mathrm{NaOH} \xrightarrow{\text{conc.}} \mathrm{C_{6}H_{5}CH_{2}OH} + \mathrm{C_{6}H_{5}COONa}$ $\mathrm{CH_{3}COOH} + \mathrm{Cl_{2}} \xrightarrow{\text{red}\text{ }\text{P}} \mathrm{CH_{2}ClCOOH} + \mathrm{HCl}$
(1) Propanone oxime: $\mathrm{(CH_3)_2C=NOH}$ (and $\mathrm{H_2O}$)
(2) Cannizzaro reaction: benzyl alcohol ($\mathrm{C_6H_5CH_2OH}$) and sodium benzoate ($\mathrm{C_6H_5COONa}$)
(3) Hell-Volhard-Zelinsky reaction: chloroethanoic acid ($\mathrm{CH_2ClCOOH}$) and HCl
Answer (ii)
AI| Pair | Test | Observation |
| (1) Benzaldehyde and benzoic acid | Add $\mathrm{NaHCO_3}$ solution | Benzoic acid gives brisk effervescence of $\mathrm{CO_2}$; benzaldehyde gives none |
| (2) Propanal and propanone | Iodoform test ($\mathrm{I_2}$ + NaOH, warm) | Propanone gives a yellow precipitate of $\mathrm{CHI_3}$; propanal gives none |
From ISC 2018 Specimen Chemistry Paper 1, question 18(a).
Check your working with the Distinguish two organic compounds: the chemical tests that tell two organic compounds apart, with what each one shows.