Answer:
The pH will be very High.
Explanation:
The electron chain is responsible for generating the Proton Motive Force, which pumps H+ (protons) into the inter membrane space, to lower the pH.Therefore if Cyanide inhibits the ETC, the PMF will be stopped.
Hydrogen ions will not be pumped into the inter-membrane space,to lower the pH of the medium for increase acidity. Hence, electrochemical gradient from the diffusion of H+ back into the matrix will not be generated,
Energy for ATP synthesis by ATPase Enzyme will not be produced. Therefore ATP synthesis will stop.