Explanation:
- When a bond is formed by transfer of electrons from one atom to another then it results in the formation of an ionic bond.
An ionic bond is generally formed by a metal and a non-metal.
For example, lithium is an alkali metal with atomic number 3 and its electronic distribution is 2, 1.
And, chlorine is a non-metal with atomic number 17 and its electronic distribution is 2, 8, 7.
So, in order to complete their octet lithium needs to lose an electron and chlorine needs to gain an electron.
Hence, both of then on chemically combining together results in the formation of an ionic compound that is, lithium chloride (LiCl).
An ionic compound is formed by LiCl because lithium has donated its valence electron to the chlorine atom.
- On the other hand, if a bond is formed by sharing of electrons between the two chemically combining atoms then it is known as a covalent bond.
For example, 
is a covalent compound as electrons are being shared by each oxygen atom.
Answer:
CO32−
Explanation:
We have to consider the valencies of the polyatomic ions involved. Recall that it is only a polyatomic ion with a valency of -2 that can form a compound which requires two sodium ions.
When we look closely at the options, we will realize that among all the options, only CO32− has a valency of -2, hence it must be the required answer. In order to be double sure, we put down the ionic reaction equation as follows;
2Na^+(aq) + CO3^2-(aq) ---------> Na2CO3(aq)
Answer:
0.42%
Explanation:
<em>∵ pH = - log[H⁺].</em>
2.72 = - log[H⁺]
∴ [H⁺] = 1.905 x 10⁻³.
<em>∵ [H⁺] = √Ka.C</em>
∴ [H⁺]² = Ka.C
∴ ka = [H⁺]²/C = (1.905 x 10⁻³)²/(0.45) = 8.068 x 10⁻⁶.
<em>∵ Ka = α²C.</em>
Where, α is the degree of dissociation.
<em>∴ α = √(Ka/C) </em>= √(8.065 x 10⁻⁶/0.45) = <em>4.234 x 10⁻³.</em>
<em>∴ percentage ionization of the acid = α x 100</em> = (4.233 x 10⁻³)(100) = <em>0.4233% ≅ 0.42%.</em>
