Question

The number of moles of cl- ions needed to combine completely with 0.25 moles of mg+2 ions is: 0.50 0.125 0.75 0.25

Answer 1

Mg²⁺ + 2Cl⁻ = MgCl₂

n(Mg²⁺)=0.25 mol

n(Cl⁻)=2n(Mg²⁺)

n(Cl⁻)=2*0.25=0.50 mol

Answer 2

0.50 moles of Cl-

Step-by-step explanation:

Magnesium is an alkaline earth metal and belongs to group II A in the periodic table. The oxidation state of Mg is +2 i.e. it forms a doubly charged cation Mg2+

Chloride is a halogen and belongs to group VII A in the periodic table. The oxidation state is -1 i.e. it forms an anion, Cl-

When Mg2+ and Cl- combine, the product formed is an ionic compound MgCl2. The balanced equation is:

Mg^{2+}+ 2Cl^{-}\rightarrow MgCl_{2}

2 moles of Cl- ions combine with 1 mole of Mg2+ to form the product

i.e. the ratio of Mg2+ : Cl- = 1:2

Therefore, 0.25 moles of Mg2+ would need 0.50 moles of Cl-