Tag: chemistry

Questions Related to chemistry

When magnesium oxide reacts with $HCl$, it gives:

  1. ${H} _{2}O$

  2. ${O} _{2}$

  3. salt and water

  4. $MgCl _2$


Correct Option: C
Explanation:

When magnesium oxide reacts with $HCl$, it gives salt and water
$\displaystyle MgO + 2HCl \rightarrow MgCl _2 + H _2O$

The black color of copper oxide turns blue on treating with $HCl$ because of:

  1. formation of cupric chloride

  2. formation of water

  3. release of hydrogen

  4. release of carbon dioxide


Correct Option: A
Explanation:

When $HCl$ reacts with copper oxide, the black color of copper oxide turns blue due to formation of its corresponding salt i.e. calcium chloride. Water is formed along with salt.

The more non-metallic character of an element represents,  _______  oxide.

  1. less acidic

  2. more acidic

  3. neutral

  4. more basic


Correct Option: B
Explanation:

Generally, more metallic character of an element represent, formation of more basic oxide. Likewise, the more non-metallic character an element has, the more acidic oxide. The metallic character of an element can be determined by its position on the periodic table.

$SO _3 + Mg(OH) _2 \rightarrow $

  1. no reaction

  2. $Mg(OH) _2$

  3. $Mg(SO _4)$

  4. $H _2O$


Correct Option: C,D
Explanation:

$SO _3$ is a non-metallic oxide which is acidic in nature and reacts with base to give a general neutralization reaction by forming a salt and water as


$SO _3+Mg(OH) _2\rightarrow MgSO _4+H _2O$
                                            Salt        water
Correct option - C,D

The formation of metal oxide on the surface of metal is called:

  1. cathodising

  2. anodizing

  3. acidification

  4. none of above


Correct Option: B
Explanation:

The formation of metal oxide on the surface of metal is called anodizing. For example: aluminium oxide is formed on the surface of aluminium when it is exposed to air which prevents its corrosion.

Black copper (II) oxide dissolves in colourless sulfuric acid to give:

  1. yellow solution of copper (II) sulfate

  2. blue solution of copper (II) sulfuric acid

  3. blue solution of copper (II) sulfate

  4. none of above


Correct Option: C
Explanation:

$Cu(II) oxide\longrightarrow CuO$


$CuO+ H _2SO _4\longrightarrow \underbrace{CuSO _4} _{(Blue\quad coloured)}+H _2O$

Copper(IIoxide, a black solid and colourless dilute sulfuric acid react to produce copper(II) sulfate, giving a characteristic blue colour to the solution.

Hence, the corret option is $C$

The metal in metal oxide replaces the __________ from acid.

  1. water

  2. hydrogen

  3. oxide

  4. none of above


Correct Option: B
Explanation:

Metals oxides will react with dilute acids to give a salt and water. The metal replaces the hydrogen. 

$2NaOH  +  C{O} _{2}   \rightarrow$

  1. ${Na} _{2}C{O} _{3}$

  2. $NaHC{O} _{3}$

  3. $NaC{O} _{3}$

  4. $Na{O} _{2}$


Correct Option: A
Explanation:

When a metal oxide reacts with a base corresponding salt and water are produced.

$2NaOH  +  C{O} _{2}   \rightarrow   {Na} _{2}C{O} _{3}  +  {H} _{2}O$

What is a metal oxide?

  1. Metal + oxygen

  2. Metal + ozone

  3. Metal + water

  4. Metal + water + oxygen


Correct Option: A
Explanation:

An oxide is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. 

Hence,option A is correct.

State True or False.
Some metal oxides are acidic or amphoteric in nature. 

  1. True

  2. False


Correct Option: A
Explanation:

Some metal oxides are acidic or amphoteric in nature and form salts with base in neutralization reaction. For example, aluminum oxide reacts with sodium hydroxide to form sodium aluminate.