Question

6 Which factor listed below is most impotant in determining the streagth of an eayacid A) the sle of the melecule ) the abilty of the melecule to change atomic orientation C) the identity of the contral atam in the molecule Dy the unber of oxygen atoa present in thee melecule E sose of thne LAslai, 7. The buffer capacity of a buffer isceases by A) Increasing amount of only the weak acid B) Increasing amount of only the conjugste base Increasing amount of both waak acid and conjugate base in solaution D) ncreasing amount of NaOH E t cannet be increased by any means A 60.0g ample of CaCo, is heated so 940 K in a L.00 L evacuated container, where it reacts acconding to the following equation E CaCO/s) Ca0()+ CO(a) Afler equilibrium is atained, the pressure of COig) is 30.0 mm Hg. When the experiment is repeated using 120.0 g CaCOs what is the new equilbrium pressure P A) 15.0mm He B) 30.0 mm Hg C)60.0 mm Hg D) 30 mm Hgs Ps 60.0mm Hg 9. The solubility of some compound A Xwhere A is some trivalent metal and X is some bivalent non-metal is y molL. ts solubility prodact (Ksp) will be A) 6y B) 64y C) 36y D) 108y 10. Which one of the following statements regarding K is false? A. pK is 14.00 at 25 C. B. The value of K is always 1.0x 10-14 C. K changes with temperature. D. The value of K shows that water is a weak acid. E. K is known as the ion product of water. Nitrous acid, HNO, has Ka - 4.5 x 10 What is the best description of the species present in a 0.1 M solution of nitrous acid? A) HNO(aq) is the predominant species; much smalller amounts of H'(aq) and NO:(aq) exist. B) H'(aq) and NO (aq) are the predominant species; much smaller amounts of HNO:(aq) exist C) Only H'(aq) and NO: (aq) are present in measurable amounts. D) HNO(aq), H'(aq), and NO:(aq) are all present in comparable amounts. bond formed between a transition metal ion and a Lewis base will be c bond dinate covalent bond B) pure covalent bond D) Hydrogen bond

Answer 1

Solution:

6) The correct option is D

The strength of oxyacids depends upon the number of oxygen atoms present in molecule. It increases with increasing the number of oxygen atoms.

7) The correct option is C

Buffer capacity increases with increasing the concentrations of both weak acids and conjugate base. The buffer capacity of a buffer changes with pH and pH depends upon the concentrations of weak acid and its conjugate base.

pH = pka + log [Conjugate base] / [Weak acid]

8) Option A

For the raction,

CaCO3 (s) = CaO(s) + CO2(g)

60 g caco3 contains = 60 g /100 g mol-1 = 0.6 mol

120 g CaCO3 = 120 g / 100 g mol-1 = 1.2 mol

Increase in number of moles causes increase the volume hence causes decrease in pressure.

9) Option D

A2X3 = 2A+ + 3X-

Ksp = (2y)^2 ( 3y)^3

Ksp = 108 y^5

10) Option is D

Kw does not explain that water is a weak acid. It shows water in neutral.

Other options are correct.