English Medium इयत्ता १० - CBSE Important Questions for Science

If you are asked to report your observations about the following two properties of acetic acid, what would you report?
(i) Odour
(ii) Effect on litmus

If you take a pinch of sodium hydrogen carbonate powder in a test-tube and add drop-by-drop acetic acid to it, what would you observe immediately? List any two main observations.

Which element exhibits the property of catenation to maximum extent and why?

Write the name and molecular formula of an organic compound having its name suffixed with 'ol' and having two carbon atoms in its molecule. Write balanced chemical equation to indicate what happens when this compound is heated with excess conc. H₂SO₄ and the name of main product formed. Also state the role of conc. H₂SO₄ in the reaction.

An organic compound 'P' is a constituent of wine. 'P' on reacting with acidified K₂Cr₂O₇ forms another compound 'Q'. When a piece of sodium is added to 'Q' a gas 'R' evolves which burns with a pop sound. Identify P, Q and R and write the chemical equations of the reactions involved.

A student is studying the properties of acetic acid in his school laboratory. List two physical and two chemical properties which he must observe and note in his record book.

Write the name and molecular formula of the first member of the homologous series of alkynes.

Elements forming ionic compounds attain noble gas electronic configuration by either gaining or losing electrons from their valence shells. Explain giving reason why carbon cannot attain such a configuration in this manner to form its compounds. Name the type of bonds formed in ionic compounds and in the compounds formed by carbon. Also explain the reason why carbon compounds are generally poor conductors of electricity.

A student puts a drop of acetic acid first on a blue litmus paper and then on a red litmus paper. He would observe that
(A) the red litmus paper turns colourless and there is no change in the blue litmus paper.
(B) the red litmus paper turns blue and the blue litmus paper turns red.
(C) there is no change in the red litmus paper and the blue litmus paper turns red.
(D) there is no change in the blue litmus paper and the red litmus paper turns blue.

While studying saponification reactions, the following comments were noted down by the students :
(I) Soap is a salt of fatty acids.
(II) The reaction mixture is basic in nature.
(III) In this reaction heat is absorbed.
(IV) This reaction is not a neutralisation reaction.
Which of these are the correct comments ?
(A) I and III only
(B) I, II and III
(C) II, III and IV
(D) I and II only

A student is studying the properties of acetic acid. List two physical properties of acetic acid he observes. What happens when he adds a pinch of sodium hydrogen carbonate to this acid? Write any two observations.

Name the functional group present in the following compound:
HCOOH

Name the functional group present in the following compound:
C₂H₅CHO

Define homologous series of organic compounds. List its two characteristics. Write the name and formula of the first member of the series of alkenes.

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

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

Which one of the following are the correct observations about acetic acid?

(A) It turns blue litmus red and smells like vinegar

(B) It turns blue litmus red and smells like burning sulphur

(C) It turns res litmus blue and smells like vinegar

(D) It turns red litmus blue and has a fruity smell

In a tabular form, differentiate between ethanol and ethanoic acid under the following heads:

(i) Physical state

(ii) Taste

(iii) NaHCO₃ test

(iv) Ester test

Write a chemical reaction to show the dehydration of ethanol.