Class 8 Materials Metals And Non Metals CBSE Questions & Answers

Class 8 · Materials Metals And Non Metals

This is Science Class 8 Materials Metals and Non Metals CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
These days precious metals are used for :
  • A
    currency
  • B
    electric wires
  • C
    investment
    Correct
  • D
    resistances
2
Phosphorus immediately oxidises in air, so its ignition temperature is :
  • A
    slightly higher than room temperature
  • B
    270\(^\circ {\text{ c}}\)
  • C
    lower than room temperature
    Correct
  • D
    equal to the room temperature
3
Read the following statements :i) Nitrogen is an inactive liquid non metal.ii) Fluorine is an extremely reactive gaseous non metal.
  • A
    both are wrong
  • B
    statement ii) is correct but i) is wrong
    Correct
  • C
    both are correct
  • D
    statement i) is correct but ii) is wrong
4
Common salt when reacts with sulphuric acid produces :
  • A
    sodium hydride
  • B
    sulphur dioxide
  • C
    nitric acid
  • D
    hydrochloric acid
    Correct
5
Displacement reactions are not shown by :
  • A
    Cl
  • B
    O
    Correct
  • C
    I
  • D
    Br
6
Carbonic acid formation involves reaction between :
  • A
    Carbon dioxide and hydrogen gas
  • B
    Carbon dioxide and oxygen
  • C
    Carbon dioxide and hydrochloric acid
  • D
    Carbon dioxide and water
    Correct
7
Noble metals are different from base metals because :
  • A
    they behave nobly with other elements
  • B
    they are non resistant to corrosion and oxidation
  • C
    their economic value is low so not used nobly
  • D
    they are resistant to corrosion and oxidation
    Correct
8
Read the following statements :i) Ash of Magnesium forms Magnesium oxide with water.ii) Magnesium oxide is a basic oxide.
  • A
    statement ii) is correct but i) is wrong
    Correct
  • B
    both are wrong
  • C
    both are correct
  • D
    statement i) is correct but ii) is wrong
9
High density of most metals is due to :
  • A
    tightly packed crystal lattice
    Correct
  • B
    malleability and ductility
  • C
    electrical conductivity and electron cloud
  • D
    high reactivity
10
The molecular formula of Sodium oxide should be :
  • A
    \({\text{N}}{{\text{a}}_{\mathbf{3}}}{\text{O}}\)
  • B
    NaO
  • C
    $N{a_{\mathbf{2}}}O$
    Correct
  • D
    \({\text{Na}}{{\text{O}}_{\mathbf{2}}}\)
11
Mercury is used in switches due to :
  • A
    its medicinal property
  • B
    its gaseous natue
  • C
    its liquid nature
    Correct
  • D
    all the above
12
Formula of sulphurous acid & sulphuric acid are _____ respectively :
  • A
    \({\text{HS}}{{\text{O}}_{\mathbf{3}}}\) & \({{\text{H}}_{\mathbf{2}}}{\text{S}}{{\text{O}}_{\mathbf{4}}}\)
  • B
    \({{\text{H}}_{\mathbf{3}}}{\text{S}}{{\text{O}}_{\mathbf{3}}}\) & \({{\text{H}}_{\mathbf{2}}}{\text{S}}{{\text{O}}_{\mathbf{4}}}\)
  • C
    \({{\text{H}}_{\mathbf{2}}}{\text{S}}{{\text{O}}_{\mathbf{3}}}\) & \({{\text{H}}_{\mathbf{2}}}{\text{S}}{{\text{O}}_{\mathbf{4}}}\)
    Correct
  • D
    \({{\text{H}}_{\mathbf{2}}}{\text{S}}{{\text{O}}_{\mathbf{4}}}\) & \({{\text{H}}_{\mathbf{2}}}{\text{S}}{{\text{O}}_{\mathbf{4}}}\)
13
Sodium and Potassium can even float on water because :
  • A
    they have very low density
    Correct
  • B
    they are best ductile metals
  • C
    they are very reactive
  • D
    they are very soft
14
The acidic oxides react with water to form :
  • A
    bases
  • B
    hydrogen gas
  • C
    salt
  • D
    acids
    Correct
15
Metals are used for making wires of musical instruments due to :
  • A
    ductility
  • B
    malleability
  • C
    sonority
    Correct
  • D
    conductivity