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The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at 0°C is
The for the decomposition of (if its degree of dissociation under one atomic pressure is 90%) is
In a reversible chemical reaction at equilibrium, if the concentration of any one of the reactants is doubled, then the equilibrium constant will
Enthalpy of neutralization of H3PO3 acid is –106.68 KJ/mole using NaOH. If enthalpy of neutralization of HCl by NaOH is –55.84 KJ/mole. Calculate ΔHionisation of H3PO3 into its ions. (in KJ)
H3PO3 → 2H+ + HPO3–2
2H+ + 2OH– → 2H2O
ΔH = –55.84 × 2 = –116.68
–106.68 = ΔHion – 55.84 × 2
ΔHion = 5KJ/mol
An aqueous solution of 6.3 g of oxalic acid dihydrate is made upto 250 mL. The volume of0.1 N NaOH required to completely neutralise 10 mL of this solution is :
100 mL of 0.6 M acetic acid is shaken with 2 g activated carbon. The final concentration of the solution after adsorption is 0.5 M. What is the amount of acetic acid adsorbed per gram of carbon.
What will be the resultant pH when 150 mL of an aqueous solution of HCl (pH = 2.0) is mixed with 350 mL of an aqueous solution of NaOH (pH = 12.0)?
How many grams of NH4Cl should be dissolved per litre of solution to have a pH of 5.13 ? Kb for NH3 is 1.8 × 10–5.
NH4Cl is a salt of strong acid and weak base for solutions of such salts.
pH = 1/2 [pKW – log C – pKb]
⇒ 10.26 = 14 – log C – 4.74
⇒ log C = 9.26 – 10.26 = –1.0
∴ C = 10–1 M
[NH4Cl] = 10–1 M
= 10–1 × 53.5 gL–1
= 5.35 gL–1