just some titration problems (1 Viewer)

[xx06]

1.11.732 g sodium hydrogen carbonate was dissolved in water and made up to exactly 500 mol. 25 ml of this soln was titrated with sulfuric acid soln and required 22.8 ml. Calculate the molarity of the sulfuric acid solution and required 33.8 ml. Calculate the molarity of the sulfuric acid soln. An approximately 0.2 mol/ L sodium hydroxide soln was then standardised by titrating 25 ml of it with this sulfuric acid soln; 26.2 ml of the acid was required. Calculate th emolarity of the hydroxide soln.
2. Oxalic acid dihydrate, (COOH)2. 2H2o, can be used as a primary standard for standardising alkali solution. 0.291 g of diprotic oxalic acid required
3.Concentrated sulfuric acid is 98% pure by weight and has a density of 1.83g/L. What volume of concentrated acid is needed to prepare 1L of 0.40 mol/ L solution?
4. Calculate the % of purity of a sample of calcium hydroxide if 0.206 g of the sample required 42.6 ml of 0.104 mol/L nitric acid for exact neutralisation.
5. A chemist suspects that her supply of sodium sulfite has been partially oxidised to sulfate by exposure to air over a long time. To determine the % of sulfite in her sample , she dissolved 0.781 g in her 50 ml 0.38mol/L HCl (aq) with the 0.144 mol/L sodium hydroxide soln. 35.4 ml was required. Calculate th eweight % sodium sulfite in her sample.

6. How do you know whether certain ions wil react with water

 

[Dreamerish*~]

1. 11.732 g sodium hydrogen carbonate was dissolved in water and made up to exactly 500 mol. 25 ml of this soln was titrated with sulfuric acid soln and required 22.8 ml. Calculate the molarity of the sulfuric acid solution and required 33.8 ml. Calculate the molarity of the sulfuric acid soln. An approximately 0.2 mol/ L sodium hydroxide soln was then standardised by titrating 25 ml of it with this sulfuric acid soln; 26.2 ml of the acid was required. Calculate th emolarity of the hydroxide soln.

Do you mean 500 mL?

2NaHCO_3(aq) + H₂SO_4(aq) [FONT=&quot]→ [/FONT]2H₂O_(l) + Na₂SO_4(aq) + 2CO_2(g)

n = m/M

.: n_NaHCO3 = 11.732/84 = 0.13967

Concentration = 0.13967/0.5 = 0.2793 M

1 being NaHCO₃ and 2 being H₂SO₄:

C₁V₁/C₂V₂ = 2/1 = 2

(0.2793 x 0.022)/(C₂ x 0.0228) = 2

C₂ = 0.135 (3 d.p.)

Normally I'd do the rest too, but uni just started and it's crazy. I'll come back to it later if nobody else has answered it already.

 

[PLooB]

Please use paragraphs!!

 

[followme]

hey i don't think your working is right
can't understand

 

[Riviet]

hey i don't think your working is right
can't understand

What don't you understand?

 

[XcarvengerX]

2. Oxalic acid dihydrate, (COOH)2. 2H2o, can be used as a primary standard for standardising alkali solution. 0.291 g of diprotic oxalic acid required

Is the question finished?

3.Concentrated sulfuric acid is 98% pure by weight and has a density of 1.83g/L. What volume of concentrated acid is needed to prepare 1L of 0.40 mol/ L solution?

Is this in the syllabus? Can someone please do this? What 98% pure means?

6. How do you know whether certain ions wil react with water

Acid and base ions will be hydrolised by water. Even water can react with water itself:
H₂O (l) + H₂O (l) = H₃O⁺(aq) + OH^-(aq).
Anything with (aq) after its formula is basically in water solution and probably in equilibrium if there is no disturbance.