English Medium कक्षा १० - CBSE Important Questions for Science

Write the name and molecular formula of a carbon compound having its name suffixed with "-ol" and having two carbon atoms in its molecule. With the help of a chemical equation indicate what happens when this compound is heated with excess conc. H₂SO₄.

Classify the following reaction into different type:

AgNO₃(aq) + NaCl(aq) →AgCl(s) + NaNO₃(aq)

Classify the following reaction into different type:

\[\ce{2KClO3(s)->[\Delta] 2KCl(aq) + 3O2(g)}\]

Classify the following reaction into different type:

Zn + CuSO₄ → ZnSO₄ + Cu

When a potassium iodide solution is added to a solution of lead (II) nitrate in a test tube, a precipitate is formed.

What is the colour of this precipitate? Name the compound precipitated.

When a potassium iodide solution is added to a solution of lead (II) nitrate in a test tube, a precipitate is formed.

Write the balanced chemical equation for this reaction.

When a potassium iodide solution is added to a solution of lead (II) nitrate in a test tube, a precipitate is formed.

List two types of reactions in which this reaction can be placed.

A student mixes sodium sulphate powder in barium chloride powder. What change would the student observe on mixing the two powders? Justify your answer and explain how he can obtain the desired change.

Give reasons for the following:
The reaction of iron (III) oxide [Fe₂O₃] with heated aluminum is used to join cracked machine parts.

Alloys are homogeneous mixtures of a metal with a metal or non-metal. Which among the following alloys contain non-metal as one of its constituents?

Which of the following is the correct observation of the reaction shown in the above set up?

These consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:

Assertion: Silver bromide decomposition is used in black and white photography.

Reason: Light provides energy for this exothermic reaction.

Identify the types of reaction mentioned above. Give one example for type in the form of a balanced chemical equation.

Identify the types of reaction mentioned above. Give one example for type in the form of a balanced chemical equation.

1. Identify the gasses evolved at the anode and cathode in the above experimental set up.
2. Name the process that occurs. Why is it called so?
3. Illustrate the reaction of the process with the help of a chemical equation.

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

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

A metal nitrate 'A' on heating gives a metal oxide along with evolution of a brown coloured gas 'B' and a colourless gas, which helps in burning. Aqueous solution of 'A' when reacted with potassium iodide forms a yellow precipitate.

1. Identify 'A' and 'B'
2. Name the types of the reactions involved in the above statement.

State the change in colour observed in following case mentioning the reason:

A piece of zinc is dipped in ferrous sulphate solution.

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.

Identify the product which represents the solid state in the above reaction.