Metals and Non-metals — Class 10 Science PYQs

Which of the following is a poor conductor of electricity ?

Solder is an alloy of

Study the following table and select the correct option :

Which one of the following non-metals exists as liquid at room temperature ?

When an element ‘X’ reacts with water, it starts floating. Identify the element 'X' :

When $\ce{Mg}$ metal is treated with hot water, it starts floating on the surface of the water. The reason for its different behaviour is :

The reaction of calcium with cold water is :

Which of the following is an amphoteric oxide ?

Which gas is evolved when magnesium metal reacts with very dilute $\ce{HNO3}$ ?

Write balanced equations for the reactions of the following :
(a) Iron with steam
(b) Calcium with water

Read the following passage and answer the questions that follow :
When metals are burnt in air, they form oxides. Metal oxides are generally basic in nature. But some metal oxides show both acidic as well as basic behaviour. Most metal oxides are insoluble in water, but some of these dissolve in water to form alkalis. Different metals show different reactivities towards oxygen. Metals such as sodium and potassium react vigorously whereas metals like silver and gold do not react with oxygen even at high temperature.
(a) Why are metals like sodium and potassium kept immersed in kerosene oil ?
(b) Why does copper metal turn black on heating?
(c) (i) What are the amphoteric oxides ? Give two examples.
OR
(c) (ii) (I) Name a water soluble metal oxide. Write the chemical equation for its reaction with water.
(II) Why do silver and gold not react with oxygen even at high temperature ?

Which one of the following metals does not react with cold water?

Which one of the following metals neither reacts with cold water nor reacts with hot water but reacts with steam ?

On reaction with dilute $\ce{HCl}$, which of the following pair of metals will evolve hydrogen gas ?

(c) (ii) (I) Why highly reactive metals cannot be obtained from their oxides by using carbon as a reducing agent ?
(II) Why solder, an alloy of lead and tin, is used for welding electrical wires together ?

Read the following passage and answer the questions that follow :
One student was comparing the reactivity of different metals for his science project. He added iron filings in four test tubes A, B, C and D containing aqueous solutions of $\ce{ZnSO4}$, $\ce{CuSO4}$, $\ce{FeSO4}$ and $\ce{Al2(SO4)3}$.
(i) In which of the test tubes will he observe the reaction to be the most vigorous and why ?
(ii) Write a balanced equation for the reaction involved.

Comment on the following properties of ionic compounds and give reason in support of your answer :
(i) Physical nature
(ii) Melting and boiling points

(i) Give reasons for the following :
(I) Ionic compound have generally high melting points and boiling points.
(II) Solder, an alloy of lead and tin, is used for welding electrical wires.
(III) Carbon cannot reduce the oxides of $\ce{Na}$ or $\ce{Mg}$.
(ii) The reaction of compound ‘X’ with aluminium is used to join railway tracks :
(I) Identify the compound ‘X’.
(II) Name the reaction.
(III) Write the balanced chemical equation of the reaction of compound ‘X’ with aluminium.

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

Which one among the following alloys has mercury as one of its constituents ?

Read the following passage and answer the questions given below :
Most of metals occur in combined state in form of ores. Carbonate ores are converted into oxides by calcination and sulphide ores by roasting. Oxides are reduced with suitable reducing agent like carbon to get free metal. Highly reactive metals like – $\ce{Al}$, $\ce{Mg}$ are also used as reducing agents to obtain metal from their oxides. Most reactive metals are obtained by electrolytic reduction of their molten ores. Alloying is a very good method of improving the properties of a metal. We can get desired properties by this method. The electrical conductivity and melting point of an alloy is less than that of pure metals.
(a) Why carbonate or sulphide ores are converted to oxides before extraction of metal from it?
(b) Write a reaction in which Aluminium is used as a reducing agent to obtain metal from its oxide.

(c) (i) How is copper obtained from its ore ($\ce{Cu2S}$) ? Give equations of the reactions.

(c) (i) With the help of chemical equations, show the extraction of copper from its ore
ce{Cu2S}.

OR
(b) Give reasons :
(i) Metal sulphides and carbonates should be converted to their metal oxides in the process of extraction of metals.
(ii) Aluminium oxide is considered as an amphoteric oxide.
(iii) Metals like $\ce{Na}$, $\ce{K}$, $\ce{Ca}$ and $\ce{Mg}$ are never found in their free state in nature.

(i) Which method will be used to convert each of them to their respective metal oxides ?
(a) Carbonate ore (b) Sulphide ore
(ii) Write a chemical reaction to illustrate the use of aluminium for joining cracked railway tracks.
(iii) During extraction of metals, electrolytic refining is used to obtain pure metals. Which material will be used as anode and cathode for the refining of copper metal by this process ?

(i) Write all the reactions involved in the extraction of $\ce{Zn}$ from $\ce{ZnS}$.
(ii) Hydrogen gas is not evolved when most of the metals react with nitric acid. Give reason.

A student notices that her silver jewellery turned dull and had a grey-black coating over it after wearing for a few months. What results in the change in colour of the silver metal ?

Galvanization is a process of coating iron articles with a thin layer of zinc to prevent iron from rusting. The iron is protected even if the zinc coating is scratched and iron is exposed. Which of the following is/are true about how zinc prevents the rusting of iron ?
(P) A galvanised iron article does not undergo oxidation.
(Q) The zinc coating prevents contact of iron with air.
(R) Zinc provides continuous protection to iron from rusting.