English Medium Class 10 - CBSE Question Bank Solutions

Assertion (A): Melting point and boiling point of ethanol are lower than that of sodium chloride.

Reason (R): The forces of attraction between the molecules of ionic compounds are very strong.

A metal 'M' on reacting with dilute acid liberates a gas 'G'. The same metal also liberates gas 'G' when reacts with a base.

1. Write the name of gas 'G'.
2. How will you test the presence of this gas?
3. Write chemical equations for the reactions of the metal with (1) an acid and (2) a base.

Give reason for the following:

During reproduction inheritance of different proteins will lead to altered body designs.

To balance the following chemical equation the value of x and y should respectively be:

\[\ce{2NaOH + xAl_2O_3->yNaAlO_2 + H_2O}\]

When aqueous solutions of potassium iodide and lead nitrate are mixed an insoluble substance separates out. The chemical equation for the reaction involved is: 

The electron dot structure of chlorine molecule is:

A student took a small amount of copper oxide in a conical flask and added dilute hydrochloric acid to it with constant stirring. He observed a change in colour of the solution. 

1. Write the name of the compound formed and its colour.
2. Write a balanced chemical equation for the reaction involved.

Why is acidified water considered to be a good conductor of electricity?

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

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

Name the following:

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

Show the covalent bond formation in nitrogen molecule.

• Assertion: The probability of survival of an organism produced through sexual reproduction is more than that of an organism produced through asexual mode.
• Reason: Variations provide advantages to individuals for survival.

Dil. HCl is added to Zn granules. How will you prove that chemical change has taken place here? Support your response with two arguments.

Exlain the following:

\[\ce{H3PO3}\] is not tribasic acid.

A plant growth inhibitor hormone which causes wilting of leaves is ______.

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

Why should a magnesium ribbon be cleaned before burning in air?

What type of oxides are formed when non-metals combine with oxygen?

What does an electric circuit mean?