Sample: Commercial bleach Technical specifications: - Composition: sodium hypochlorite (NaClO) and demineralized water; - Active chlorine content: 2.00 to 2.50% (m/m); - Active ingredient: sodium hypochlorite (NaClO). - Approximate density: 1.08 g/ml; - Physical Aspect: Liquid; - Color: Colorless. Note: the active chlorine content refers to the chlorine gas produced from the following reaction: ClO¯ + Cl¯ + 2H+ ⇋ Cl₂(g) + H₂O Data: M.A.: H = 1.0079 g/mol; Na = 22.989769 g/mol; S = 32.065 g/mol; I = 126.90447 g/mol; O = 15.9994 g/mol; Cl = 35.453 g/mol. Material available in the laboratory's warehouse: Reagents: Distilled water; standardized solution of sodium thiosulfate (Na₂S₂O₃), at a concentration of 0.0500 mols/L; 20% KI solution; glacial acetic acid and; starch gum (indicator). Glassware: Bechers of all sizes available on the market; 50, 100, 150, 200 and 250 ml Erlenmeyer flasks; 10.00 and 25.00 mL volumetric pipettes; 25.00 mL burette; 25.00, 50.00 and 100.0 mL volumetric flasks. Calculate the possible concentration range of the original sample (bleach), in mols/L, of sodium hypochlorite and choose the most appropriate concentration for the sample under analysis: (A) 0.268 mols/L (B) 0.686 mols/L (C) 0.0762 mols/L (D) 0.351 mols/L
Sample: Commercial bleach
Technical specifications:
- Composition: sodium hypochlorite (NaClO) and demineralized water;
- Active chlorine content: 2.00 to 2.50% (m/m);
- Active ingredient: sodium hypochlorite (NaClO).
- Approximate density: 1.08 g/ml;
- Physical Aspect: Liquid;
- Color: Colorless.
Note: the active chlorine content refers to the chlorine gas produced from the following reaction:
ClO¯ + Cl¯ + 2H+ ⇋ Cl₂(g) + H₂O
Data:
M.A.: H = 1.0079 g/mol; Na = 22.989769 g/mol; S = 32.065 g/mol; I = 126.90447 g/mol; O = 15.9994 g/mol; Cl = 35.453 g/mol.
Material available in the laboratory's warehouse:
Reagents:
Distilled water; standardized solution of sodium thiosulfate (Na₂S₂O₃), at a concentration of 0.0500 mols/L; 20% KI solution; glacial acetic acid and; starch gum (indicator).
Glassware:
Bechers of all sizes available on the market; 50, 100, 150, 200 and 250 ml Erlenmeyer flasks; 10.00 and 25.00 mL volumetric pipettes; 25.00 mL burette; 25.00, 50.00 and 100.0 mL volumetric flasks.
Calculate the possible concentration range of the original sample (bleach), in mols/L, of sodium hypochlorite and choose the most appropriate concentration for the sample under analysis:
(A) 0.268 mols/L
(B) 0.686 mols/L
(C) 0.0762 mols/L
(D) 0.351 mols/L
Given the active chlorine content of the commercial bleach = 2.00 % to 2.50 % (m/m)
Since % m/m of active chlorine is given, let's consider 100 g of the bleach.
density of bleach = 1.08 g/mL
=> volume of 100 g bleach, V = 100 g * (1 mL / 1.08 g) = 92.6 mL
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