Question

21. Write the balanced chemical equation for the following
a) Zinc + Silver nitrate Zinc nitrate + Silver
b) Calcium hydroxide + carbon dioxide Calcium Carbonate +Water​

Answer 1

Answer

Reaction

When Zinc reacts with silver nitrate zinc nitrate and silver are formed as a product and silver basically is formed as a precipitate.

Balanced equation.

Zn + 2Ag NO₃ ⟶ Zn( NO₃ ) ₂ + 2Ag.

Here 2 moles of silver nitrate are required where is one mole of zinc metal is required this will ultimately lead to the production of one mole of zinc nitrate as well as 2 moles of silver as a precipitate.

Now moving on to the second reaction ,

Reaction

When calcium hydroxide reacts with carbon dioxide calcium carbonate as well as water is formed.

Balanced equation

Ca(OH)2 + CO2⟶CaCO3 + H2O.

Hence one mole of calcium hydroxide on reaction with one mole of carbon dioxide give this calcium carbonate along with one mole of water.

Hence this equation doesn't need to be balanced much as it contains one mole of product as well as one mole of reactant on both the sides.

Answer 2

$\underline{\green{\textsf{Answer:-}}}$

$\bold{Zn + 2AgNO_3 \implies Zn(NO_3)_2 + 2Ag}$

$\bold{Ca(OH)_2 + CO_2 \implies CaCO_3 + H_2O}$

$\underline{\green{\textsf{Explanation:-}}}$

Balanced Equation:

• The equation in which mass of reactants = the mass of products is said to be a balanced equation
• An equation should be balanced. Because, LAW OF CONSERVATION OF MASS says that, Atoms are neither created nor destroyed in a chemical reaction. Hence, mass of reactants = products
• A chemical reaction is balanced by using stoichiometric co-efficients.

Skeletal Equation:

• Unbalanced chemical equation is called as skeletal equation
• It dosen't obeys the law of conservation of mass

ACCORDING TO THE QUESTION:

Zinc + silver Nitrate ----> Zinc Nitrate + Silver

$\bold{Zn + AgNO_3 \implies ZnNO_3 + Ag}$

We can write the eq. as above mentioned.

But, Here valencies of the combining elements are not satisfied

Valency:

Combining capacity of an element is called as valency

Hence, The eq. should be written as,

$\bold{Zn + 2AgNO_3 \implies Zn(NO_3)_2 + 2Ag}$

In the above reaction

>> You can also mention the STATES of the each substance or compound.

Ex: $Zn _(s)$

(s) - solid

>> The numericals before the compounds are called as Stoichiometric coefficients.

Similary, You can also write the 2nd reaction as,

$\bold{Ca(OH)_2 + CO_2 \implies CaCO_3 + H_2O}$