List of top Science Questions on Chemistry in Everyday Life asked in CBSE Class X

Mohan heated ethanol with a compound 'X' in the presence of a few drops of conc. \( H_2SO_4 \) and observed a sweet smelling compound 'Y' is formed. When 'Y' is treated with sodium hydroxide it gives back ethanol and a compound 'Z'.
(i) Identify 'X', 'Y' and 'Z'.
(ii) Write the role of conc. \( H_2SO_4 \) in the reaction.
(iii) Write the chemical equations involved and name the reactions.
Write chemical equations for the following :
(I) Oxidation of ethanol by acidified K₂Cr₂O₇.
(II) Hydrogenation of ethene.
Give reasons for the following:
(I) Covalent compounds are poor conductor of electricity.
(II) Soap does not form lather in hard water.
(III) Carbon shows catenation but silicon does not.
Explain chlor-alkali process with chemical equation. Name the products formed at anode and cathode.
What happens when : (a) An iron nail is dipped in copper (II) sulphate solution ?
(b) Potassium iodide solution is mixed with lead nitrate solution ?
(c) Silver chloride is exposed to sunlight ?
Write balanced chemical equations to support your answer.
Why does one feels pain and irritation when stung by honey-bee?
Rubbing of baking soda on the stung area gives relief. How?
Assertion (A): Carbon shares its valence electrons with other atoms of carbon or with atoms of other elements.
Reason (R): The shared electrons belong to the outermost shells of both the atoms and lead to both atoms attaining the noble gas configuration.
The natural sources of oxalic acid, lactic acid and methanoic acid respectively are:
Which of the following is a poor conductor of electricity?
The hydrocarbons with general formula \( C_nH_{2n} \) represents:
Which one of the following can be used as an acid-base indicator by a visually impaired (blind) student?
(i) \( \text{AgNO}_3 + \text{NaCl} \rightarrow \text{NaNO}_3 + \text{AgCl} \)
(ii) \( \text{K}_2\text{SO}_4 + \text{BaCl}_2 \rightarrow \text{BaSO}_4 + 2\text{KCl} \)
Which of the following options clearly describes both the reactions?
The gases evolved on heating lead (II) nitrate crystals are :