Metals and Non-Metals — Science STD 10 — Question

With the help of labelled diagrams, describe an activity to show that acids produce ions only in aqueous solutions.

State one characteristic each of the chemical reaction which takes place when:

1. Dilute hydrochloric acid is added to sodium carbonate.
2. Lemon juice is added gradually to potassium permanganate solution.
3. Dilute sulphuric acid is added to barium chloride solution.
4. Quicklime is treated with water.
5. Wax is burned in the form of a candle.

A non-metal A which is the largest constituent of air, when heated with H₂in 1:3 ratio in the presence of catalyst (Fe) gives a gas B. On heating with O₂, it gives an oxide C. If this oxide is passed into water in the presence of air, it gives an acid D which acts as a strong oxidizing agent.

1. Identify A, B, C and D.
2. To which group of the periodic table, does this non-metal belongs?

State one use each of the following metals:
Copper, Aluminium, Iron, Silver, Gold, Mercury

The metal M reacts vigorously with water to form a solution S and a gas G. The solution S turns red litmus to blue whereas gas G, which is lighter than air, burns with a pop sound. Metal M has a low melting point and it is used as a coolant in nuclear reactors.

1. What is metal M?
2. What is solution S? Is it acidic or alkaline?
3. What is gas G?
4. Write a balanced chemical equation for the reaction which takes place when metal M reacts with water.
5. Is this reaction exothermic or endothermic?

A strip of metal X is dipped in a blue coloured salt solution YSO₄. After some time, a layer of metal Y from the salt solution is formed on the surface of metal strip X. Metal X is used in galvanisation whereas metal Y is used in making electric wires. Metal X and metal Y together form an alloy Z.

1. What could metal X be?
2. What could metal Y be?
3. Name the metal salt YSO₄.
4. What type of chemical reaction takes place when metal X reacts with salt solution YSO₄? Write the equation of the chemical reaction involved.
5. Name the alloy Z.

Mendeleev predicted the existence of certain elements not known at that time and named two of them as eka - aluminium, and eka - silicon.

1. Name the element which has taken the place of (i) eka - aluminium, and (ii) eka - silicon.
2. Mention the period/ periods of these elements in the modern periodic table.
3. Write the group/ groups of these elements in the modern periodic table.
4. Classify these elements as metals, non - metals or metalloids.
5. How many valence electrons are present in the atoms of each of these elements?​​​​​​

State one use each of the following non-metals:
Hydrogen, Carbon (as Graphite), Nitrogen, Sulphur

i. Define a decomposition reaction. How can we say that (I) electrolysis of water, and (II) blackening of silver bromide when exposed to sunlight, are decomposition reactions? Mention the type of energy involved in each case.
ii. The type of reactions in which (I) calcium oxide is formed, and (II) calcium hydroxide is formed are opposite reactions to each other. Justify this statement with the help of chemical equations.

What is meant by:

1. Displacement reaction, and
2. Double displacement reaction? Explain with the help of one example each.