Question

7) For the chemical reaction NH(aq) + HCl(aq) → NH"(aq) + Cl(aq) the acid and conjugate base are a)NH(acid): NH" (conjugate base) b) NH, (acid), CT (conjugate base) c) HCl(acid); NH (conjugate base) d) HCl(acid), NH, (conjugate base) c) HCI (acid) Conjugate base) 8) A buffer solution is formed by adding 0.0100 moles of potassium dihydrogen phosphate (KH-PO.) and 0.0100 moles of potassium hydrogen phosphate (K_HPO) into 1.000 liters of water. When 0.0010 moles of NaOH is added to this solution, what will happen? a) The pH of the solution will decrease by a large amount (>0.10 pH units) b) The pH of the solution will decrease by a small amount (<0.10 pH units) c) The pH of the solution will be exactly the same as before the addition of the NaOH d) The pH of the solution will increase by a large amount ( > 0.10 pH units) e) The pH of the solution will increase by a small amount (< 0.10 pH units) 9) For which of the following substances does phosphorus (P) have the largest value for oxidation number? a) Na,P b) H.PO, c) PO, d) PF c) P. 10) Which of the following is always true for the oxidation numbers in an oxidation-reduction reaction? a) The final value for the oxidation number for atoms of the element being oxidered must be positive b) The initial value for the oxidation number for atoms of the element being oxidized must be positive c) The value for the oxidation number for atoms of the element being exidized must increase as we go from reactants to products d) Botha and b e) None of the above is always true 11) Which of the following is true of a catalyst? a) A catalyst is a substance b) A catalyst, when added to a reaction system, increases the rate at which the reaction occurs c) A catalyst is neither produced nor consumed as a reaction proceeds d) Both band e) Botha and bandc 12) In the Arrhenius equation, the value for A, the pre-exponential factor, depends on a) the collision frequency (number of collisions per unit volume and unit time) b) the orientation factor (the fraction of collisions that have an orientation favorable for reaction to occur) c) the activation energy (the minimum energy needed to convert reactants into products) d) Botha and b e) Botha and bands

Answer 1

7- Ans - option E

Explanation-

According to Bronsted and Lowry concept,  

i) An acid is a species which has the ability to lose H+ ion in solution and get converted to its conjugate base

ii) A base is a species which has the ability to accept the H+ in solution and get converted to its conjugate acid

So on this basis, for the given acid-base reaction

NH3 + HCl ------> NH4⁺ + Cl^-

So here

i) NH3 acts as a base by accepting H+ and get converted to its conjugate acid NH4+

ii) HCl acts as acid by losing H+ and get converted to its conjugate base Cl-