English Medium कक्षा १० - CBSE Important Questions for Science

A carbon compound ‘A’ having melting point 156K and boiling point 351K, with molecular formula C2H6O is soluble in water in all proportions.

1. Identify ‘A’ and draw its electron dot structure.
2. Give the molecular formulae of any two homologues of ‘A’.

Anita added a drop each of diluted acetic acid and diluted hydrochloric acid on pH paper and compared the colors. Which of the following is the correct conclusion?

Shristi heated Ethanol with a compound A in presence of a few drops of concentrated sulphuric acid and observed a sweet smelling compound B is formed. When B is treated with sodium hydroxide it gives back Ethanol and a compound C.

1. Identify A and C
2. Give one use each of compounds A and B.
3. Write the chemical reactions involved and name the reactions.

What is the role of concentrated Sulphuric acid when it is heated with Ethanol at 443 K. Give the reaction involved.

Reshu by mistake forgot to label the two test tubes containing Ethanol and Ethanoic acid. Suggest an experiment to identify the substances correctly? Illustrate the reactions with the help of chemical equations.

Write the chemical formula of two consecutive homologous of organic compounds having functional group - OH. 

What happens to the (i) boiling point and (ii) solubility of organic compounds of a homologous series as the molecular mass increases?

Consider the following molecular formulae of carbon compounds:

(i) CH₃COOH (ii) CH₃OH (iii) C₂H₆ (iv) C₃H₄ (v) C₄H₈ 

1. Which one of these compounds belongs to homologous series of alcohols?
2. Identify the compound having triple bond between carbon-carbon atoms.
3. Write the molecular formula of the first member of the homologous series to which CH₃COOH belongs.
4. Write the general formula of the series to which the compound C₄H₈ belongs.

Consider the carbon compounds having following molecular formula:

(i) C₂H₂ (ii) C₂H₅ (iii) C₃H₇OH (iv) C₂H₆COOH (v) CH₃CHO

1. Identify which one of the above compounds, is a member of aldehyde series.
2. Write the general formula of the series to which compound C₂H₂ belongs.
3. Which one of the above compounds has triple bonds between carbon-carbon atoms?
4. Write the molecular formula of the first member of the homologous series to which the compound C₃H₇OH belongs.

Consider the carbon compounds having following molecular formula:

(i) C₃H₆ (ii) C₃H₈ (iii) C₄H₆ (iv) C₆H₆ (v) C₆H₁₂

1. State the number of double covalent bonds present in C₃H₈.
2. Write the formula of first member of the homologous series to which the carbon compound C₄H₆ belongs.
3. Which one of the above compounds forms a ring structure of carbon atoms?
4. Identify, which of the above compounds, is a member of alkane series.

Name and draw the electron dot structure of first homologue of alkynes series.

It is observed that covalent compounds are had conductors of electricity. Give reason. 

Carbon can neither form C^4- cation nor C⁴ anion. Why?

Draw electron dot structure of Ethanol.

Name the third homologue of alcohols.

Name the third homologue of aldehydes.

Name the following:

\[\ce{CH3 - CH2CH = CH2}\]

Show the covalent bond formation in nitrogen molecule.

Raina while doing certain reactions observed that heating of substance ‘X’ with a vinegar-like smell with a substance ‘Y’ (which is used as an industrial solvent.) in the presence of conc. Sulphuric acid in a water bath gives a sweet-smelling liquid ‘Z’ having molecular formula C₄H₈O₂. When heated with caustic soda (NaOH), ‘Z’ gives back the sodium salt and the compound ‘Y’.

Identify ‘X’, ‘Y’, and ‘Z’. Illustrate the changes with the help of suitable chemical equations.

A spatula full of sodium carbonate is taken in a test tube and 2 mL of dilute ethanoic acid is added to it.

Write a chemical equation for the reaction.

The number of single and double bonds present in a molecule of benzene (C₆H₆) respectively, are ______.