Question

Write the following equation in the ionic form:
a) \[Mn{O_2} + 4HCl \to MnC{l_2} + 2{H_2}O + C{l_2}\]
b) \[2NaHC{O_3} + {H_2}S{O_4} \to N{a_2}S{O_4} + {H_2}O + C{O_2}\]
A.
a) \[Mn{0_2} + 4{H^ + } + 4C{l^ - } \to M{n^{2 + }} + 2C{l^ - } + 2{H_2}O + C{l_2}\]
b) \[2N{a^ + } + 2HCO_3^ - + 2{H^ + } + SO_4^ - \to 2N{a^ + } + SO_4^ - + 2{H_2}O + {O_2}\]
B.
a) \[2Mn{O_2} + 8{H^ + } + 4C{l^ - } \to 2M{n^{2 + }} + 2C{l^ - } + 4{H_2}O + C{l_2}\]
b) \[2N{a^ + } + 2HCO_3^ - + 2{H^ + } + SO_4^ - \to 2N{a^ + } + SO_4^ - + 2{H_2}O + {O_2}\]
C.
a) \[Mn{O_2} + 4{H^ + } + 4C{l^ - } \to M{n^{2 + }} + 2C{l^ - } + 2{H_2}O + C{l_2}\]
b) \[2N{a^ + } + 2HCO_3^ - + 2{H^ + } + SO_4^ - \to 2N{a^ + } + SO_4^ - + 2{H_2}O + {O_2}\]
D. None of these

Answer 1

Hint: A chemical equation represents the substances that are involved in a chemical reaction i.e. reactants and products. The balanced chemical equation is the one that has the same number of atoms on both sides of a reaction.

Complete step by step answer:
According to the law of conservation of mass, in an isolated system, mass is neither created nor destroyed by any chemical or physical transformations. There are examples of chemical reactions.
When Calcium carbonate reacts with hydrochloric acid, it produces calcium chloride and releases carbon dioxide gas. From this, we know that calcium carbonate and hydrochloric acid are the reactants and the products will be calcium chloride, carbon dioxide, and water.
 \[CaC{O_3}(s) + HCl(aq) \to CaC{l_2}(aq) + C{O_2}(g) + {H_2}O\]
We can balance this equation by counting the particular atom on both sides and making them equal on each side. Calcium, carbon, and oxygen atoms are the same on both sides but hydrogen and chlorine atoms are double on the right side. Therefore, we get the balanced chemical equation by putting 2HCl on the left side as:
 \[CaC{O_3}(s) + 2HCl(aq) \to CaC{l_2}(aq) + C{O_2}(g) + {H_2}O\]
When Dilute sulphuric acid reacts with zinc granules, it produces zinc sulphate and releases hydrogen gas. Because zinc is more reactive than hydrogen, it easily displaces hydrogen from sulphuric acid. This can be written in equation form as now we know the reactants and products.
 \[{H_2}S{O_4}(aq) + Zn(s) \to ZnS{O_4}(aq) + {H_2}(g)\]
We can see that this reaction is already balanced. The number of atoms of zinc, sulphur, hydrogen, and oxygen is the same on both sides.
When Calcium oxychloride reacts with hydrochloric acid, it forms calcium chloride, water, and liberates chlorine. The chemical equation for the same is-
 \[CaOC{l_2}(s) + 2HCl(aq) \to CaC{l_2}(aq) + {H_2}O(l) + C{l_2}(g)\]
The atoms involved are balanced on both sides.
Now, the given chemical reactions are,
a) \[Mn{O_2} + 4HCl \to MnC{l_2} + 2{H_2}O + C{l_2}\]
b) \[2NaHC{O_3} + {H_2}S{O_4} \to N{a_2}S{O_4} + {H_2}O + C{O_2}\]
The ionic form of these two equation is,
a) \[Mn{O_2} + 4{H^ + } + 4C{l^ - } \to M{n^{2 + }} + 2C{l^ - } + 2{H_2}O + C{l_2}\]
b) \[2N{a^ + } + 2HCO_3^ - + 2{H^ + } + SO_4^ - \to 2N{a^ + } + SO_4^ - + 2{H_2}O + C{O_2}\]

So, the correct option is, A.

Note: We can easily measure the heat absorbed or evolved by a chemical reaction. Errors occur because some of the heat may escape before it can be measured – we need ideally to measure the total heat energy evolved or absorbed, which can be done if all the heat is transferred to a liquid whose temperature we measure, however, some heat is inevitably lost to the environment.