Chemical Reactions and equations

Why should we rub a Magnesium ribbon with sand paper before using it?

• To remove the layer of carbon-di-oxide formed on it.

• To remove the layer of chlorine formed on it.

• To remove the layer of oxygen formed on it.

• To remove the layer of neon formed on it.

Magnesium and oxygen react with each other and form

• Magnesium di oxide.

• Magnesium triphosphate

• Magnesium oxide.

• Magnesium Hydroxide

What is the chemical equation of Aluminium Hydroxide?

• Al2O3Al_2O_3

  Al2

  ​O3

  ​

• Al3O2Al_3O_2

  Al3

  ​O2

  ​

• Al(OH)2Al(OH)_2

  Al(OH)2

  ​

• Al(OH)3Al\left(OH\right)_3

  Al(OH)3

  ​

A chemical reaction in which two or more substances combine with each other to form a single substance is called?

• Double displacement reaction

• Displacement reaction

• Combination reaction

• Decomposition rection

What is the chemical formula of Quick lime?

• CaO

• CaOH

• NaOH

• MgO

What is the chemical formula of Glucose?

• C6H6O12C_6H_6O_{12}

  C6

  ​H6

  ​O12

  ​

• C6H12O5C_6H_{12}O_5

  C6

  ​H12

  ​O5

  ​

• C6H12O6C_6H_{12}O_6

  C6

  ​H12

  ​O6

  ​

• C12O6H3C_{12}O_6H_3

  C12

  ​O6

  ​H3

  ​

• Decomposition

• Double displacement

• Dispalcement

• Combination

By which method can we decompose water molecule?

• Heating

• Electrolysis

• Oxidation

• Reduction

Which of the following is not the characteristics of chemical reactions?

• Change in colour

• Change in temperature

• Evolution of gas

• None of the above

Quicklime reacts with water to form?

• Cao

• Ca(OH)2Ca\left(OH\right)_2

  Ca(OH)2

  ​

• NH4O2NH_4O_2

  NH4

  ​O2

  ​

• LimeLime

  Lime