Carbon and its Compounds — Science STD 10 — Question

Write a short note on ‘Chipko Andolan’ (Hug the Trees Movement).

On adding dilute hydrochloric acid to copper oxide powder, the solution formed is blue-green.

1. Predict the new compound formed which imparts a blue-green colour to solution.
2. Write a balanced chemical equation of the reaction which takes place.
3. On the basis of the above reaction, what can you say about the nature of copper oxide?

In an experiment to study the scattering of light by passing a beam of white light through a colloidal solution of sulphur in a transparent glass tank:

1. Which colour is observed from the front of the glass tank? Does this colour correspond to the colour of sky on a clear day or the colour of sky around the sun at sunset?
2. Which colour is observed from the sides of the glass tank? Does this colour correspond to the colour of sky on a clear day or the colour of sky around the sun at sunset?

What are the components of the transport system in human beings? What are the functions of these components?

Two lenses A and B have power of (i) + 2 D and (ii) -4D respectively. What is the nature and focal length of each lens?

1. Name one antacid. How does it help to relieve indigestion in stomach?
2. A farmer treats the soil with quicklime or calcium carbonate. What is the nature of soil? Why does the farmer treat the soil with quicklime?

1. Write Joule’s law of heating.
2. Two lamps, one rated 100W; 220V, and the other 60W; 220V, are connected in parallel to electric mains supply. Find the current drawn by two bulbs from the line, if the supply voltage is 220V.

State where an object must be placed so that the image formed by a concave mirror is:

1. Erect and virtual.
2. At infinity.
3. The same size as the object.

When a metal X is treated with cold water, it gives a basic salt Y with molecular formula XOH (Molecular mass = 40) and liberates a gas Z which easily catches fire. Identify X, Y and Z and also write the reaction involved.