Question

Part 2. (3pt) If we pump HF gas into the buffer solution in Part 1 (without changing the solution volume), which of the following statement should be true? Statement (I): The concentration of fluoride ion F will decrease. Statement (Il): The pH of the buffer will decrease. Statement (IIl): The concentration of H30* will decrease. a) (0) b) (l) c) (IlI) d)(0) and () e) (0) and (II) f (Il) and (II) 8)), () and (II) h) none of the above Part 3. (3pt) Which of the following processes will increase the pH of the buffer in Part 1? Process (I): adding more water Process (): dissolving some solid NaOH(s) into the solution (without changing solution volume) Process (II): dissolving some solid KF(s) into the solution (without changing solution volume a) (0) b) (l) c) (IIl) d) (0) and (I) e) (1) and (IlI) f() and (II) g) (0),() and (II) h) none of the above 2. (3pt) If 0.10-mol weak acid HF (Ka 7.2 x 10) mixes with 0.10-mol weak base CH3NH2 (Kb 1-L solution, the pH of the final mixture should be 7 a) greater than b) equal to c) less than d) cannot be judged 4.4 x 104) into 3. (3pt) For which of the following reactions will the entropy of the system decrease? a) 2 NH3(g) N2(g) +3 H2(g) b) 2 C(s) +O(g) 2 CO(g) c) CaCOs(s) CaO(s) + CO2(g) d) 2 NO2(g) -> N204(g) e) NaOH(s) Na (aq)+ OH (aq) 4. (3pt) A simple fire extinguisher is made by mixing baking soda solution (NaHCOs) and vinegar solution (CH,COOH). After mixing, the solution temperature rises. Meanwhile, carbon dioxide gas is produced to put out fire. What are the signs of A..H, A.S, and A G for this process to mix NaHCOs (aq) and CHaCOOH (aq)? a) Δ,H > 0,A,S < 0, Δ,G > 0 b) Δ.Η > 0, AS>0,A,G > 0 d) A,H <0, AS<0, A-G<0 f) none of the above

question 2 and 3 could be answer is a complete question

Answer 1

Answer : (2) option (c) pH of final mixture would be less than 7 . Whole derivation and calculation I have shown in the image attached:

(Note : in weak acid , weak base case if pKa < pKb , pH of solution will be less than 7 and vice versa)

"To calulate Hag weak acid and weak hats 써. Ka CHF e, Fh

ka.にも E-カ K,

Answer : (3) option (d) entropy of the system decreases when no. of moles of gases are less on the product side in comacompar to reactant side .

In (d) reaction , 2 mol of NO_{​​​​​2} is converted into 1mol of N_{​​​​​​2} O_{​​​​​​4} , disorderness of the system decreases hence entropy increases. In all other reaction , no. Of moles of gases are more in product side .

(Note: entropy of solid substance are taken to be zero when comparing in the reaction)