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प्रश्न
Calculate the amount of benzoic acid (C6H5COOH) required for preparing 250 mL of 0.15 M solution in methanol.
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उत्तर
Given: Volume of solution (V) = 250 mL
Molarity (M) = 0.15 M
Molar mass of benzoic acid (C6H5COOH) = 12 × 6 + 5 × 1 + 12 × 1 + 16 × 2 + 1 × 1
= 72 + 5 + 12 + 32 + 1
= 122 g mol−1
Molarity (M) = `"Number of moles (N) "/"Volume in litres (V)"`
Number of moles = M × V
= 0.15 × 0.250
= 0.0375 mol
Mass = Moles × Molar mass
= 0.0375 × 122
= 4.575 g
Thus, 4.575 g of benzoic acid is required to prepare 250 mL of 0.15 M solution in methanol.
संबंधित प्रश्न
The substance ‘X’, when dissolved in solvent water gave molar mass corresponding to the molecular formula ‘X3’. The van’t Hoff factor (i) is _______.
(A) 3
(B) 0.33
(C) 1.3
(D) 1
Define the term abnormal molar mass.
How van’t Hoff factor is related to the degree of dissociation?
How will you convert the following in not more than two steps:
Benzoic acid to Benzaldehyde
Give reasons for the following
Elevation of the boiling point of 1 M KCl solution is nearly double than that of 1 M sugar solution.
The Van't Hoff factor (i) for a dilute aqueous solution of the strong elecrolyte barium hydroxide is (NEET) ______.
Phenol dimerizes in benzene having van’t Hoff factor 0.54. What is the degree of association?
The van’t Hoff factor (i) accounts for ____________.
Van’t Hoff factor i is given by the expression:
(i) i = `"Normal molar mass"/"Abnormal molar mass"`
(ii) i = `"Abnormal molar mass"/"Normal molar mass"`
(iii) i = `"Observed colligative property"/"Calculated colligative property"`
(iv) i = `"Calculated colligative property"/"Observed colligative property"`
Maximum lowering of vapour pressure is observed in the case of ______.
When 9.45 g of ClCH2COOH is added to 500 mL of water, its freezing point drops by 0.5°C. The dissociation constant of ClCH2COOH is x × 10−3. The value of x is ______. (Rounded-off to the nearest integer)
[\[\ce{K_{f(H_2O)}}\] = 1.86 K kg mol−1]
The degree of dissociation of Ca(NO3)2 in a dilute aqueous solution containing 7 g of the salt per 100 g of water at 100°C is 70%. If the vapour pressure of water at 100°C is 760 mm. The vapour pressure of the solution is ______ mm.
Consider the reaction
\[\begin{bmatrix}\begin{array}{cc}
\phantom{.......}\ce{CH3}\\
\phantom{....}|\\
\ce{CH3CH2CH2 - \overset{⊕}{N} - CH2CH3}\\
\phantom{....}|\\
\phantom{.......}\ce{CH3}
\end{array}\end{bmatrix}\]\[\ce{OH^- ->[Heat] ?}\]
Which of the following is formed in a major amount?
When 19.5 g of F – CH2 – COOH (Molar mass = 78 g mol−1), is dissolved in 500 g of water, the depression in freezing point is observed to be 1°C. Calculate the degree of dissociation of F – CH2 – COOH.
[Given: Kf for water = 1.86 K kg mol−1]
Why is the value of van't Hoff factor for ethanoic acid in benzene close to 0.5?
Calculate Van't Hoff factor for an aqueous solution of K3 [Fe(CN)6] if the degree of dissociation (α) is 0.852. What will be boiling point of this solution if its concentration is 1 molal? (Kb = 0.52 K kg/mol)
