A student takes about 6 ml of distilled water in each of the four test tubes P, Q, R and S. He then dissolves an equal amount of four different salts namely, sodium chloride in 'P', potassium chloride in 'Q', calcium chloride in 'R' and magnesium chloride in 'S'. - Science

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A student takes about 6 ml of distilled water in each of the four test tubes P, Q, R and S. He then dissolves an equal amount of four different salts namely, sodium chloride in 'P', potassium chloride in 'Q', calcium chloride in 'R' and magnesium chloride in 'S'. Next, he then adds 10 drops of soap solution to each test tube and shakes its contents. The test tubes in which scum (insoluble substance) is formed with soap are:

(A) P and Q

(B) Q and R

(C) R and S

(D) Q and S

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Solution

Scum is formed by reaction of soap with calcium and magnesium salts in water. Test tubes R and S contain calcium chloride and magnesium chloride, respectively. Therefore, scum will be formed in these two tubes.

Hence, the correct option is C.

Concept: Ethanoic Acid
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2013-2014 (March) Delhi Set 1

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RELATED QUESTIONS

Ethanoic acid has a .................... odour.
(a) Rotten eggs
(b) Pungent
(c) Vinegar-like
(d) Mild


The molecular formula of acetic acid is _________ .
(a) CH3COOH
(b) CH3 – CH3
(c) C6H6
(d) C2H4


Consider the following comments about saponification reactions:

I. Heat is evolved in these reactions.

II. For quick precipitation of soap, sodium chloride is added to the reaction mixtures.

III. Saponification reactions are a special kind of neutralisation reactions.

IV. Soaps are basic salts of long-chain fatty acids.

The correct comments are

(a) I, II and III

(b) II, III and IV

(c) I, II and IV

(d) Only I and IV


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


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


Complete the following chemical equations : C2H5OH + Na →


Choose the correct alternative and rewrite the following: 

Acetic acid ..................


When zinc powder is added to acetic acid ______________

(a) the mixture becomes warm
(b) a gas is evolved
(c) the colour of the mixture becomes yellow
(d) a solid settles at the bottom


What is an oxidising agent? 


 Consider the following organic compound:
CH3OH, C2H5OH, CH3COCH3, CH3COOH, C2H5COOH, C4H9COOC2H5, CH4, C2H6, CH3CHO, HCHO
Out of these compound:

Which compound is added to alcohol to denature it?


Write the names of three compounds that can be oxidized directly or in stages to produce acetic acid.


Complete:

The next higher homologue of ethanoic acid is …………………


On adding 2 mL acetic acid to 2 mL of water in a test tube, it was observed that

(A) a clear and transparent solution is formed

(B) a white precipitate is formed almost immediately

(C) two separate layers were formed

(D) a colourless and odourless gas is evolved


Explain the following term with an example.

Oxidant


Under what conditions does ethane get converted to
(a) Ethyl alcohol (b) acetic acid


What is vinegar and glacial acetic acid?


What is the main constituent of vinegar?


Why is pure acetic acid also known as glacial acetic acid?


Give reason for the following :

Ethyne is more reactive than ethane


Draw the structural formula for the following:

Ethanoic acid


A compound X when treated with an organic acid Y (having vinegar-like smell) in the presence of the acid Z, forms a compound P which has a fruity smell.

(a) Identify X, Y, and Z

(b) Write the structural formula of X and Y.

(c) What type of compound P is?

(d)Name the above reaction.

(e) If compound X and Y both have 2 carbon atoms. Write the reaction.


Ethanoic acid _________.


Choose the correct alternative and rewrite the following:

Some acetic acid is treated with solid NaHCO3, the resulting solution will be _________________.


Rewrite the following statement by selecting the correct option.
The formula of ethanoic acid is _____________.


Two statements are given - one labelled Assertion (A) and the other labelled Reason (R).
Assertion (A): Esterification is a process in which a sweet-smelling substance is produced.
Reason (R): When esters react with sodium hydroxide an alcohol and sodium salt of carboxylic acid are obtained.


CH3–CH2–CHO : propanal : : CH3–COOH : _______


Ketone : –CO– : : Ester : _______


Write the molecular formula of the given compound.

Ethanoic acid


Ester is a sweet-smelling compound.


Explain the following reaction with an example.

Esterification


Explain the following reaction with an example.

Saponification


What are catalysts?


Give a chemical reaction in which a catalyst is used.


Write the characteristics of ethanoic acid.


Observe the figure and write the answers to the following questions.

  1. Write the name of the reaction shown in the following figure.
  2. Write the above chemical reaction in the form of a balanced equation.
  3. Write the name of the product produced in the above reaction, write a use.
  4. Write the name of the catalyst used in the above reaction.

Write the answers to the questions by observing the following figure.

  1. Write the chemical reaction shown in the figure above in the form of a balanced equation.
  2. Write the name of the gas coming out of the large test tube in the above chemical reaction.
  3. Why do small bubbles appear in the small test tube?
  4. What is the change in colour of lime water?

Ethanoic acid turns ______ litmus to ______


Give the balanced chemical equation of the following reaction:

Neutralization of NaOH with ethanoic acid.


Ester is formed by the reaction between ______.


Draw the structural diagram of: 

Ethanoic acid


In the presence of the acid catalyst, ethanoic acid reacts with ethanol and ______ ester is produced.


The reaction between acetic acid and sodium carbonate is shown in the following figure.

Answer the questions with the help of a diagram.

  1. Which gas does come out as effervescence in the big test tube?
  2. What is the colour change in the lime water present in the small test tube?
  3. Write the related reaction.

Ethanoic acid reacts with the basic salt, sodium carbonate, to form a salt, named ______, water and carbon dioxide gas.


Bubbles are seen in the test tube during the preparation of lime water.


What happens when a small piece of sodium is dropped in ethanol? Write the equation for this reactions.


Give the balanced chemical equation of the following reaction:

Neutralization of NaOH with ethanoic acid.


Give the balanced chemical equation of the following reaction:

Neutralization of NaOH with ethanoic acid.


Give the balanced chemical equation of the following reaction:

Neutralization of NaOH with ethanoic acid.


Name the oxidising agent used in the conversion of ethanol to ethanoic acid.


Give the balanced chemical equation of the following reaction:

Neutralization of NaOH with ethanoic acid.


Give the balanced chemical equation of the following reaction:
Neutralization of NaOH with ethanoic acid.


Give the balanced chemical equation of the following reaction:

Combustion of ethanol.


Give the balanced chemical equation of the following reaction:

Neutralization of NaOH with ethanoic acid.


Give the balanced chemical equation of the following reaction:

Neutralization of NaOH with ethanoic acid.


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