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Question
You have four test tubes, A, B, C and D containing sodium carbonate, sodium chloride, lime water and blue litmus solutions respectively. Out of these the material of which test tube/ test tubes would be suitable for the correct test of acetic/ethanoic acid?
(a) only A
(b) A and B
(c) B and C
(d) A and D
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Solution
Ethanoic (acetic) acid is an acid, and it will change blue litmus solution to red.
The chemical reaction between ethanoic (acetic) acid and sodium carbonate is:
2 CH3COOH + Na2CO3 → 2 CH3COONa + CO2 + H2O
On passing CO2 gas through lime water, the lime water turn milky. The milky apprearance of lime water is due to the formation of solid calcium carbonate (CaCO3).
Reaction:
Ca(OH)2 + CO2 → CaCO3 + H2O
Therefore, out of four test tubes A, B, C and D, only A and D test tubes would be suitable for the correct test of acetic/ethanoic acid.
Acetic acid also reacts with lime water to give calcium acetate (CH3COO)2Ca) as a product. But here it is not consider as correct test of acetic/ethanoic acid.
Reaction:
2 CH3COOH + Ca(OH)2 → (CH3COO)2Ca + 2 H2O
Hence, the correct answer is option (d).
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RELATED QUESTIONS
A student adds 2 mL of acetic acid to a test tube containing 2 mL of distilled water. He then shakes the test tube well and leaves it to settle for some time. After about 5 minutes he observes that in the test tube there is :
(A) a clear transparent colourless solution
(B) a clear transparent pink solution
(C) a precipitate settling at the bottom of the test tube
(D) a layer of water the layer of acetic acid
How esters are prepared ?
Name the gas evolved when ethanoic acid is added to sodium carbonate. How would you prove the presence of this gas?
Name one chemical compound which can be used to distinguish between ethanol and ethanoic acid.
What type of compound is formed when a carboxylic acid reacts with an alcohol in the presence of conc. H2SO4?
State any two uses of esters.
Vinegar is a solution of about:
(a) 5 to 8 per cent ethanoic acid in alcohol
(b) 5 to 8 per cent ethanoic acid in water
(c) 50 to 80 per cent ethanoic acid in water
(d) 50 to 80 per cent ethanoic acid in alcohol
On adding acetic acid to sodium hydrogen carbonate in a test tube, a student observes
(A) no reaction
(B) a colourless gas with pungent smell
(C) bubbles of a colourless and odourless gas
(D) a strong smell of vinegar
Distinguish between esterification and saponification reactions with the help of chemical equations for each.
The reaction between acetic acid and sodium carbonate is shown in the following figure.
Answer the questions with the help of a diagram.
- Which gas does come out as effervescence in the big test tube?
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- Write the related reaction.
