Free Materials: Metals & Non-Metals 03 Practice Test - 8th Grade
Question 1
Which of the following can be beaten into thin sheets?
Zinc
Phosphorus
Sulphur
Oxygen
SOLUTION
Solution : A
Zinc is a malleable metal and thus can be beaten into thin sheets. Phosphorus, sulphur and oxygen are all non-metals. Non metals are usually not malleable.
Question 2
All non-metals are non-lustrous.
SOLUTION
Solution : B
Usually, metals are lustrous and non-metals are non-lustrous. However, iodine is an exception to this rule as it is a lustrous non-metal.
Question 3
Pick the odd one from the following elements.
Gold
Potassium
Carbon
Platinum
SOLUTION
Solution : C
Out of these only Carbon (C) is a non-metal whereas the others are all metals.
Question 4
Non-metals displace hydrogen from dilute acids.
True
False
SOLUTION
Solution : B
Non-metals do not displace hydrogen from acids. Only metals that are more reactive than hydrogen can.
Question 5
When nitric acid HNO3 reacts with metals, hydrogen gas is not observed because
Metallic hydrides are formed.
Hydrogen is oxidised by nitric acid.
Metal weakly react with nitric acid.
Hydrogen is reduced by nitric acid.
SOLUTION
Solution : B
Most of the metals do not react with HNO3 because it is a strong oxidizing agent.
Since hydrogen is a reducing agent, nitric acid oxidises the hydrogen produced to water and itself undergoes reduction to give N2O, NO, NO2, N2 and NH3.
Hence, when metals (except Mn and Mg) are treated with nitric acid, hydrogen gas is not liberated.
Question 6
Why is sodium stored in kerosene in a laboratory?
Sodium is a very reactive metal and reacts vigorously at room temperature.
Sodium is less reactive and stays inert at room temperature.
Sodium is a metal.
Sodium dissolves in kerosene.
SOLUTION
Solution : A
Sodium is highly reactive. It reacts vigorously with Oxygen and water. A lot of heat is generated in this reaction. It is therefore, stored in kerosene for safety reasons.
Question 7
A substance is said to be sonorous if it _________.
produces a ringing sound when beaten
conducts water through metal pipes
conducts electricity
conducts heat
SOLUTION
Solution : A
Substances that produce a ringing sound when they are beaten are said to be sonorous. Metals are generally sonorous.
Question 8
Which of the following metal on reaction with cold water liberates hydrogen gas but does not float on water (unlike Calcium) due to its vigorous reaction (with water)?
SOLUTION
Solution : A
Metals such as potassium and sodium react violently with cold water. The reaction is so violent and exothermic that the evolved hydrogen immediately catches fire.
Question 9
Gold is more ductile than mercury.
SOLUTION
Solution : A
Ductility is the property of being able to be made into thin wires. Gold is the one of the most ductile metal and the ductility of mercury is less compared to gold.
Question 10
Which of the following metal(s) can replace copper from copper sulphate?
SOLUTION
Solution : B and C
According to the reactivity series of metals, magnesium and iron are more reactive compared to copper. Hence, they replace the copper from its salt. Whereas gold and silver are less reactive than copper, hence cannot react with copper sulphate.