Tag: chemistry

Questions Related to chemistry

Which of the following oxide is amphoteric in nature?

chemistry metals reaction of metals reactions of metals chemical properties of metals

  1. $Na _2O$

  2. $Li _2O$

  3. $K _2O$

  4. $BeO$

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Correct Option: D
Explanation:

Compounds which have the ability to react as both an acid or base are known as amphoteric in nature. 

$BeO$ is amphoteric in nature.

$Pb _3O _4$ a double oxide. is obtained by heating lead (II) oxide in air.

chemistry metals reaction of metals reactions of metals chemical properties of metals

  1. True

  2. False

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Correct Option: A
Explanation:

Lead oxide is prepared by calcination of lead II oxide in air at about 450 to 480C.
$6PbO+{ O } _{ 2 }\rightarrow { 2Pb } _{ 3 }{ O } _{ 4 }$

$\displaystyle xFe+yH _{2}O\rightarrow zFe _{3}O _{4}+wH _{2}$
What are x, y, z and w respectively ?

chemistry metals reaction of metals reactions of metals chemical properties of metals

  1. 1, 2, 3, 4

  2. 2, 3, 1, 2

  3. 3, 4, 1, 4

  4. 3, 3, 3, 3

Show answer
Correct Option: C
Explanation:

Reaction:
$\displaystyle 3Fe+4H _{2}O\rightarrow 1Fe _{3}O _{4}+4H _{2}$

Calcium is stored in kerosene.

chemistry metals reaction of metals reactions of metals chemical properties of metals

  1. True

  2. False

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Correct Option: B
Explanation:

Sodium is a highly reactive metal of alkali group and on exposure to air it forms sodium hydroxide while calcium is not reactive in nature so it is not stored in kerosene.

Metals oxides are:

chemistry metals reaction of metals reactions of metals chemical properties of metals

  1. basic in nature

  2. electrovalent (ionic) in nature

  3. able to turn red litmus solution blue

  4. all of these

Show answer
Correct Option: D
Explanation:

Metal oxides typically contain an anion of oxygen in the oxidation state of -2. Oxides which are reacted only by acids are basic oxides. Metals form basic oxides so they can turn red litmus blue as it is alkaline in nature.

What happens when water vapour is passed over a red hot iron?

chemistry metals reaction of metals reactions of metals chemical properties of metals

  1. No reaction

  2. Oxygen and $Fe{(OH)} _{2}$ are produced

  3. Hydrogen and ${Fe} _{2}{O} _{3}$ are produced

  4. Hydrogen and ${Fe} _{3}{O} _{4}$ are produced

Show answer
Correct Option: D
Explanation:

The reaction takes place as

$3Fe + 4H _2O \rightarrow Fe _3O _4 + 4H _2$
so, on passing water vapour over hot red iron we get hydrogen and $Fe _3O _4$.

A silvery-white metal $X$ reacts with water at room temperature to produce a water-soluble compound $Y$ and a colourless gas $Z$. The reaction is highly exothermic and the $Z$ catches fire immediately during the reaction. The solution of $Y$ in the water on reacting with a stoichiometric amount of dilute solution of hydrochloric acid gives a solution of $pH = 7.0$. 
The compounds $X,\ Y$ and $Z$ respectively are:

chemistry metals reaction of metals reactions of metals chemical properties of metals

  1. $Al,Al(OH) _3 $ and $ H _2$

  2. Ag, AgOH and $H _2$

  3. K, KCl and $H _2$

  4. Na, NaOH and $H _2$

Show answer
Correct Option: D
Explanation:

$2Na+H _2O\rightarrow 2NaOH+H _2+Heat$

$NaOH+HCl\rightarrow NaCl+H _2O$
$X,\ Y,\ Z$ are $Na$, $NaOH$, $H _2$

Aluminium does not react with water at room temperature because:

chemistry metals reaction of metals reactions of metals chemical properties of metals

  1. it is above hydrogen in the activity series

  2. it is below hydrogen in the activity series

  3. it is covered with a thin film of $AlN$

  4. it is covered with thin film of $Al _2O _3$

Show answer
Correct Option: D
Explanation:

Aluminium is oxidized by water at temperatures below $280^oC$  to produce hydrogen, aluminium hydroxide and heat. The challenge in this reaction is circumventing the formed oxide layer which inhibits the reaction and the expenses associated with the storage of energy by regeneration of $Al$ metal.

Which of the following metal does not react with water?

chemistry metals reaction of metals reactions of metals chemical properties of metals

  1. Beryllium

  2. Copper

  3. Iron

  4. Potassium

Show answer
Correct Option: A
Explanation:

Beryllium $(Be)$ is the only alkaline earth metal that does not react with water. This is due to its small size and high ionization energy in relation to the other elements in the group.

What happens when steam is passed over red hot iron?

chemistry metals reaction of metals reactions of metals chemical properties of metals

  1. No reaction takes place.

  2. $O _2$ and $Fe(OH) _2$ are formed.

  3. $H _2$ and $Fe _3O _4$ are formed.

  4. $H _2$ and $Fe _2O _3$ are formed.

Show answer
Correct Option: C
Explanation:

When steam is passed over red hot iron, $H _2$ and $Fe _3O _4$ are formed. The reaction is as follows:
$3Fe+4{ H } _{ 2 }O\rightarrow { Fe } _{ 3 }{ O } _{ 4 }+4{ H } _{ 2 }\uparrow $