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Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Which of the following combination are correct?

  1. Fluorspar, $FeCO _3$
  2. Zinc blende, $ZnO$

  3. Magnesite, Oxide ore

  4. Cryolite, Halide ore
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, $CaF _2$. 
Zinc sulfide $(ZnS)$ is a unique compound that forms two types of crystalline structures. These two polymorphs are wurtzite and zincblende.
 
Magnesite is a mineral with the chemical formula $MgCO _3$ (magnesium carbonate).
Cryolite $(Na _3AlF _6)$, sodium hexafluoroaluminate is a halide ore.

Hence, option $D$ is correct.
Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Which of the following are found as sulphide ores?

  1. $Al,\ Hg,\ Pb,\ F$
  2. $Fe,\ Zn,\ Pb$
  3. $Hg,\ Pb,\ Na$
  4. $F,\ Ca,\ Cu,\ Mg$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The sulfide minerals are a class of minerals containing sulfide $(S^{2−})$ as the major anion. Some sulfide minerals are economically important as metal ores. So the metal ion with this anion should have oxidation state $+2$. 
$Fe, Zn, Pb$ all three are found as  sulfide ores. Ores of these metals are known as:  Pyrite $(FeS _2)$, Sphalerite $(ZnS)$ and Galena $(PbS)$ .
Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

 Silica is added to roasted copper ore during extraction in order to remove:

  1. cuprous sulphide

  2. ferrous oxide

  3. ferrous sulphide

  4. cuprous oxide
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Silica is added during smelting in order to remove iron oxides from copper sulphide and oxides. During roasting the iron sulfides react with oxygen (in air or oxygen enriched air) to produce iron oxides (mainly as $FeO$, but with some magnetite $(Fe _3O _4))$ and sulfur dioxide. 
Copper sulfide and iron oxide can mix, but when sufficient silica is added, a separate slag layer is formed. 
The slag forming reaction is:
$FeO + SiO _2 \rightarrow FeO.SiO _2$
Slag is less dense than matte, so it forms a layer that floats on top of the matte.
Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Which of the following is used for decorating sweets?

  1. Copper foil

  2. Aluminium foil

  3. Silver foil

  4. All of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Silver foil is used for decorating sweets called Vark,  or varak (also a silver leaf, German paper) is any leaf composed of pure metals, typically silver but sometimes gold, used on South Asian sweets. The silver is edible, though flavourless.


Hence, the correct option is $C$.

Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Heat conduction is the property of __________.

  1. Non-metals

  2. Metals

  3. Metalloids

  4. All of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Heat conduction is the property of metals. In metals, valance electron is free to flow among the atoms. Because of that metals are such good conductors of electricity. These electrons can also carry energy in the form of heat and thus the metals are conductors of heat.


Hence, the correct option is $B$

Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Read the following statements and answer as true or false.
Metals occur in nature only as free elements.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Given statement is false. Very few elements occur in the free state - example: gold, platinum etc. The rest of the elements are found in the combined state as compounds such as carbonates,sulphides, oxides etc.

Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Which of the following is not the allotropic form of sulphur?

  1. Roll sulphur

  2. Monoclinic sulphur

  3. Plastic sulphur

  4. Rhombic sulphur
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Allotropes are defined as chemical elements which exist in two or more different forms, in the same physical state.

or allotropes are defined as different structural modifications of an element, the atoms of the element are bonded together in a different manner.
At present, about 30 well-characterized sulphur allotropes are known.

Commonly known allotropes of sulphur are:

  1. Rhombic sulphur
  2. Monoclinic sulphur
  3. Plastic sulphur ( also known as gamma-sulphur)

Roll sulphur is not the allotropic form of sulphur.