(A) Answer
3. What would you observe when zinc is added to a solution of iron sulphate? Write the chemical
reaction that takes place.
4. Name two metals which will displace hydrogen from dilute acids, and two metals which
5. What is meant by the reactivity series of metals?
6. How will carbon and sulphur react with oxygen? What happens when the products are dissolved
7. Name the black material present inside a pencil.
8. Name two non metals that occur in free state in air and in the combined form in the earth's crust.
in water?
ion 8
1. Metals are malleable and ductile. Explain.
2. Why are metals suitable for use in jewellery?
Answers
Explanation:
(3) When zinc is added to the solution of iron sulphate, the colour of iron sulphate solution changes. It is because zinc is more reactive than iron, therefore, it displaces iron from its solution of iron sulphate and a grey precipitate of iron and a colourless solution of zinc sulphate is formed.
(4) Iron and aluminium will displace hydrogen from dilute acids as they more reactive then hydrogen. Mercury and copper cannot displace hydrogen from dilute acids as they are less reactive than hydrogen.
(5) In chemistry, a reactivity series (or activity series) is an empirical, calculated, and structurally analytical progression of a series of metals, arranged by their "reactivity" from highest to lowest.
(6) Carbon in react with different proportion of oxygen to give CO and CO2 and SO2 in other case . after dissolving the product in water u will get H2CO3 and H2SO3(sulphurous acid)
(7) The “black thing inside the pencil” is a graphite core composed of graphite (a form of compressed carbon) and clay. This graphite core is commonly called a “lead” (like the metal), though it does not, nor has it ever, contained lead.
(1)Metals are described as malleable (can be beaten into sheets) and ductile (can be pulled out into wires). This is because of the ability of the atoms to roll over each other into new positions without breaking the metallic bond.
(2)Malleable and ductile properties of a metal make it suitable for making jewellery. Moreover, rusting and tarnishing is undesirable. If take it into account these properites, Gold and Platinum rank on top of metals list.