(i) Charcoal produces carbon dioxide on burning. This gas turns lime water milky and its solution turns blue litmus to red. Hence, it is acidic
(ii) \(\underset{Carbon}{C}+\underset{Oxygen}{O_2}⟶\underset{Carbon\ di\ oxide}{CO_2}\)

Important uses of non-metals:
(i) Non-metals are essential for our life as all living beings inhale oxygen and breath out carbon dioxide during breathing.
(ii) They are used in fertilizers to enhance the growth of plants.
(iii) Non-metal is used in the purple coloured solution that is applied on wounds as an antiseptic.
(iv)Non-metals are used in crackers.

Zinc metal can displace copper from copper sulphate solution as zinc is more reactive than copper. But copper cannot displace zinc from zinc sulphate solution because copper is less reactive than zinc.

Iron is present in our blood. Red Blood Cells (RBCs) of blood contain a respiratory pigment known as haemoglobin. Each molecule of haemoglobin contains iron atom as its important component.

When a copper vessel is exposed to moist air for a long time, it acquires a dull green coating. The green substance is the mixture of copper hydroxide [Cu(OH)₂]and copper carbonate (CuCO₃).
\(2cu+\underbrace { H_{ 2 }O+CO_{ 2 }+O_{ 2 } }_{ Moistair } \rightarrow \underbrace { Cu(OH)_{ 2 }+CuCO_{ 3 } }_{ Green\quad coating​​​​​​​ } \)

(a) Copper does not react with dilute sulphuric acid, so no reaction will take place.
(b) When iron nails are placed in copper sulphate solution, displacement reaction takes place in which iron displaces copper as iron is more reactive than copper.
Copper sulphate+ Iron\(\rightarrow \) Iron sulphate +Copper
 (CuSO₄)               (Fe)     (FeSO₄)           (Cu3)

(a) Aluminium is malleable and does not react with food items, so it is used to wrap food items.
(b) Metals are good conductors of heat and electricity. They get hot very soon on passage of current and warm the water. So, immersion rods are made up of metallic substances.
(c) Copper is less reactive than zinc, so it cannot displace zinc from its salt solution.
(d) Sodium and potassium are very reactive, they readily react with air and water, so they are stored in kerosene.

a) Chemical properties of metals:
(i) Metals react with oxygen to produce oxides which are alkaline in nature. e.g.,
\(\underset{Magnesium}{Mg}+\underset{Oxygen}{O_2}⟶\underset{Magnesium\ oxide}{2MgO}\)
(ii) Metallic oxides produce bases by reacting with water differently
\(\underset{Sodium\ oxide}{Na_2O}+\underset{Water}{H_2O}⟶\underset{Sodium\ hydroxide}{2NaOH}\)
(iii) Metals react with acid to produce hydrogen gas
\(\underset{Hydrochloric\ acid}{2HCI}+\underset{Sodium}{2Na}⟶\underset{Sodium\ chloride}{2NaCl}+\underset{Hydrogen}{H_2}\)
(iv) More reactive metals displace the less reactive metals from their compounds in an aqueous solution 
\(\underset{Copper\ Sulpahte}{CuSO_4}+\underset{Zinc}{Zn}⟶\underset{Zinc\ Sulphate}{ZnSO_4}+\underset{Copper}{Cu}\)
(b) Chemical properties of Non-metals
(i) Non-metals react with oxygen to produce oxides which are acidic in nature
\(\underset{Sulphur}{S}+\underset{Oxygen}{O_2}⟶\underset{Sulphur\ dioxide}{SO_2}\)
\(\underset{Sulphur\ dioxide}{SO_2}+\underset{Water}{H_2O}⟶\underset{Sulphurous\ Acid}{H_2SO_3}\)
(ii) Non-metals do not react with water.
(iii) Non-metals do not show displacement reactions.

(a) Firstly, gold is highly malleable and ductile. Secondly, it is not attacked by the gases of air.
(b) We prefer copper wire because it is the better electrical conductor than aluminium. However, silver is the best electrical conductor but it is very expensive.
(c) Silver is the better conductor of heat than copper.
(d) Yes, they are harmful for us because they affect throat and lungs.