Answer:
1. 0.25 moldm¯³.
2. 9.125 gdm¯³.
Step-by-step explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2HCl + Na2CO3 → 2NaCl + H2O + CO2
From the balanced equation,
The mole ratio of the acid, HCl (nA) = 2
The mole ratio of the base, Na2CO3 (nB) = 1
1. Determination of the concentration of the acid, HCl in moldm¯³.
Volume of acid, HCl (Va) = 20 cm³
Volume of base, Na2CO3 (Va) = 25 cm³
Concentration of base, Na2CO3 (Cb) = 0.1 moldm¯³
The mole ratio of the acid, HCl (nA) = 2
The mole ratio of the base, Na2CO3 (nB) = 1
Concentration of acid, HCl (Ca) =?
Cava /CbVb = nA/nB
Ca × 20 / 0.1 × 25 = 2/1
Ca × 20 / 2.5 = 2
Cross multiply
Ca × 20 = 2.5 × 2
Ca × 20 = 5
Divide both side by 20
Ca = 5/20
Ca = 0.25 moldm¯³
Thus, the concentration of the acid, HCl in moldm¯³ is 0.25 moldm¯³
2. Determination of the concentration of the acid, HCl in gdm¯³
Concentration of the acid, HCl = 0.25 moldm¯³
Molar mass of HCl = 1 + 35.5 = 36.5 g/mol
Concentration of the acid, HCl in gdm¯³ =?
Conc. in moldm¯³ = Conc. in gdm¯³ /Molar mass
0.25 = Conc. in gdm¯³ /36.5
Cross multiply
Conc. in gdm¯³ = 0.25 × 36.5
Conc. in gdm¯³ = 9.125 gdm¯³.