91影视

First, let's list the given salts and their respective ions: 1. KBr: K鈦� (potassium ion), Br鈦� (bromide ion) 2. NH鈧凜l: NH4鈦� (ammonium ion), Cl鈦� (chloride ion) 3. KCN: K鈦� (potassium ion), CN鈦� (cyanide ion) 4. K鈧侰O鈧�: 2 K鈦� (potassium ions), CO鈧兟测伝 (carbonate ion)

Now we will analyze the acidic or basic properties of each ion: - K鈦�: Since potassium belongs to Group 1 of the periodic table, it forms neutral solutions as cations of this group do not hydrolyze. - NH4鈦�: The ammonium ion behaves as a weak acid, releasing a H鈦� ion in solution: \(\mathrm{NH_4^+} \rightleftharpoons \mathrm{NH_3} + \mathrm{H^+}\) - Br鈦�, Cl鈦�: Both bromide and chloride are conjugate bases of strong acids (HBr and HCl). Therefore, they are weak bases and will cause a negligible change to the pH of the solution. - CN鈦�: The cyanide ion is the conjugate base of the weak acid, HCN. So, it behaves as a weak base by accepting a H鈦� ion from water: \(\mathrm{CN^-} + \mathrm{H_2O} \rightleftharpoons \mathrm{HCN} + \mathrm{OH^-}\) - CO鈧兟测伝: The carbonate ion is a weak base. It accepts a H鈦� ion from water, yielding bicarbonate: \(\mathrm{CO_3^{2-}} + \mathrm{H_2O} \rightleftharpoons \mathrm{HCO_3^-} + \mathrm{OH^-}\)

Based on our analysis in Step 2, let us examine each salt to see which one would produce a neutral solution: 1. KBr: K鈦� does not impact pH, and Br鈦� does not significantly change the pH. So, a KBr solution would be neutral. 2. NH鈧凜l: NH4鈦� acts as a weak acid and Cl鈦� does not significantly change the pH. This combination would result in a slightly acidic solution. 3. KCN: K鈦� does not affect the pH, but CN鈦� acts as a weak base. The solution of KCN would be slightly basic. 4. K鈧侰O鈧�: K鈦� does not affect the pH, but CO鈧兟测伝 acts as a weak base. The solution of K鈧侰O鈧� would be slightly basic. Since we are looking for a salt that forms a neutral solution, the only suitable candidate is KBr (potassium bromide). So, the identity of the unknown salt is KBr.