CBSE Class 12-science Answered

1.100 ques plz

Asked by lovemaan5500 | 30 Jan, 2019, 11:59: AM

Expert Answer

Given:

Molarity = 3 M

Density of solution : 1.25 g/ml

Mass of 3 M solution = Volume × Density

= 1000 × 1.25

Mass of 3 M solution = 1250 g

Molecular weight of Na₂S₂O₃ = `158 g/mol

Molarity space equals fraction numerator begin display style bevelled fraction numerator Mass over denominator Molar space mass end fraction end style space over denominator Volume space in space litre end fraction space space space space Mass space equals space Molarity space cross times space Volume space in space litre cross times Molar space mass space space space space space space space space space space space space space space equals 3 cross times 1 cross times 158 space space space space space space space space space space space space space space space space space space space space space space space space space space space equals space 474 space straight g space Mass space of space space water space in space solution space equals space 1250 space minus space 474 space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals 776 space straight g Moles space of space water space equals space fraction numerator Mass space over denominator Molecular space mass end fraction space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals space 776 over 18 space space space space space space space space space space space space space space space space space space space space space space space space equals space 43.1 space mol Moles space of space Na subscript 2 SO subscript 4 space equals space 3 space mol Mole space fraction space equals space fraction numerator Moles space of space Na subscript 2 SO subscript 4 over denominator Moles space of space Na subscript 2 SO subscript 4 space space space plus space Moles space of space straight H subscript 2 straight O end fraction space space space space space space space space space space space space space space space space space space space space space equals fraction numerator 3 over denominator 3 plus 43.1 end fraction space space space space space space space space space space space space space space space space space space space space space equals fraction numerator 3 over denominator 46.1 end fraction Mole space fraction space equals space 0.696 space Molality space of space Na subscript 2 SO subscript 4 space space equals space space fraction numerator 3 over denominator 776 cross times 10 to the power of negative 3 end exponent end fraction space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals 3.865 space straight m Na subscript 2 SO subscript 4 space space space plus space straight H subscript 2 straight O space space space stack rightwards arrow space space 2 Na to the power of plus space space plus space space SO subscript 4 with space on top to the power of 2 minus end exponent therefore space 1 space mole space of space Na subscript 2 SO subscript 4 space gives space 2 space moles space of space space Na to the power of plus space space and space 1 space mole space of space space SO subscript 4 to the power of 2 minus end exponent therefore space Molality space of space Na to the power of plus space equals space 2 cross times space 3.865 space space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals space 7.73 space straight m Molality space of space SO subscript 4 to the power of 2 minus end exponent space equals space 3.865 space straight m

Mole fraction of sodium thiosulphate is 0.065.

Molality of Na⁺ is 7.73 m.

Molality of SO₄^2- is 3.865 m.

Answered by Varsha | 30 Jan, 2019, 07:08: PM

CBSE Class 12-science Answered

Concept Videos

Expressing concentration of solutions

Types and concentration of solutions

Strength of Solutions

Types of Solution

CALL US / WHATSAPP

Please Login or Sign up to continue!

CBSE Class 12-science Answered

Concept Videos

Expressing concentration of solutions

Types and concentration of solutions

Strength of Solutions

Types of Solution

Choose Filters

Open In Ask A Doubt App ?

Get in Touch

Call / Whats App