If a compound AB dissociates to the extent of 75% in an aqueous solution, the molality of the solution which shows a 2.5 K rise in the boiling point of the solution is ____________ molal. (Rounded off to the nearest integer)

[K_b = 0.52 K kg mol^$$-$$1]

Electromagnetic radiation of wavelength 663 nm is just sufficient to ionise the atom of metal A. The ionization enegy of metal A in kJ mol^$$-$$1 is __________. (Rounded off to the nearest integer)

[h = 6.63 $$\times$$ 10^$$-$$34 Js, c = 3.00 $$\times$$ 10⁸ ms^$$-$$1, N_A = 6.02 $$\times$$ 10²³ mol^$$-$$1]

Consider titration of NaOH solution versus 1.25 M oxalic acid solution. At the end point following burette readings were obtained.

(i) 4.5 mL

(ii) 4.5 mL

(iii) 4.4 mL

(iv) 4.4 mL

(v) 4.4 mL

If the volume of oxalic acid taken was 10.0 mL then the molarity of the NaOH solution is ________ M. (Rounded off to the nearest integer)

Five moles of an ideal gas at 293 K is expanded isothermally from an initial pressure of 2.1 MPa to 1.3 MPa against at constant external pressure 4.3 MPa. The heat transferred in this process is _________ kJ mol^$$-$$1. (Rounded off to the nearest integer) [Use R = 8.314 J mol^$$-$$1K^$$-$$1]