Tag: chemistry

Questions Related to chemistry

Which of the following is not correct observation based on Ellingham diagram?

chemistry metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

  1. A metal can reduce the oxide of other metal which lies above it in Ellingham diagram

  2. $CO$ is more effective than $C$ as reducing agent below $170^{o}C$

  3. $\Delta G^{o}$ metal oxide is higher than of $CO _{2}$ hence oxidation of metal sulphides to oxides is not favourable

  4. Need for conversion of metal sulphide to metal oxide before reduction can be explained thermodynamically

Show answer
Correct Option: A
Explanation:

As moving down of bottom of diagram metals becomes more reactive oxides will be hard to reduce.A given metal can reduce the oxides of other metal which lies above it in Ellingham diagram.

Which of the following are properties of non-metals?

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. Lustre

  2. Can form alloys

  3. Amorphous

  4. Non-conductive towards electricity

Show answer
Correct Option: C,D
Explanation:

The properties of non-metals are:

  1. They are amorphous in nature.
  2. They are not malleable and ductile.
  3. They are poor conductors of heat and electricity.
  4. They do not form alloys.

All non-metals are solids or gases, except bromine which is liquid non-metal at room temperature.

chemistry composition of matter physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. True

  2. False

Show answer
Correct Option: A

Compare metals and non-metals with particular emphasis on solubility:

chemistry composition of matter physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. Both dissolve in solvent

  2. None of them dissolve in solvent

  3. Metal dissolve while non-metal do not dissolve in solvent

  4. Non-metal dissolve while metal do not dissolve in solvent

Show answer
Correct Option: D
Explanation:
MetalsThey do not dissolve in solvents except by chemical action. Non-metalsThey dissolve in solvents and can be re-obtained by evaporation. Example: sulphur in carbon disulphide.

Non-metal that has a metallic lustre and sublimes on heating is : 

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. chlorine

  2. bromine

  3. oxygen

  4. iodine

Show answer
Correct Option: D
Explanation:

Iodine is an intensely colored solid with an almost metallic luster. This solid is relatively volatile and it sublimes when heated to form a violet-colored gas.

The non-metallic mineral among the following is :

chemistry composition of matter physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. graphite

  2. chromite

  3. bauxite

  4. tungsten

Show answer
Correct Option: A
Explanation:

Chromite is an ore of chromium, bauxite is an ore of aluminium and tungston are metallic in nature while graphite is an allotrope of carbon and a carbonaceous compound. It is a very soft allotrope of carbon while other allotrope of carbon diamond is the hardest known element on this earth. This is because of the chemical structure of graphite which shows slippery nature of layers of carbon and presence of loose electrons.

Which non-metal has a shining surface?

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. Graphite

  2. Phosphorous

  3. Sulphur

  4. None of the above

Show answer
Correct Option: A
Explanation:

Graphite is the most stable form of carbon and so it is used as the standard state for defining the heat and formation of carbon compounds. It has a layered planar structure and the bonding between the layers is vander waals bonds. It is a non metal with shining surface.

Lustrous non-metal is :

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. Diamond

  2. Iodine

  3. Sulphur

  4. Both A and B

Show answer
Correct Option: D
Explanation:

Non-metals do not have lustre. They do not reflect light from their surface. Non-metals have dull appearance. Diamond and iodine are two exceptions and are lustrous non-metal.

Which of the following is a lustrous non-metal?

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. Chlorine

  2. Nitrogen

  3. Iodine

  4. Florine

Show answer
Correct Option: C
Explanation:

Non-metals do not have luster. They do not reflect light from their surface (exception diamond and iodine). Non-metals have dull appearance.

Which non-metal has semi-conductor property?

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. Boron

  2. Carbon

  3. Silicon

  4. Magnesium

Show answer
Correct Option: C
Explanation:

Silicon is a tetravalent metalloid. Pure silicon is used to produce silicon wafers in the semiconductor industry. Pure silicon is an intrinsic semiconductor as it conducts electron holes and increases electrical conductivity. Silicon is doped with other microelements to increas its conductivity. It is used in transistors, solar cells, semiconductor devices.