Addition of the indicator methyl orange to an unknown solution leads to a yellow color. The addition of bromthymol blue to the same solution also leads to a yellow color. (b) What is the range (in whole numbers) of possible pH values for the solution?

Video transcript

Hello everyone today. We are being told that an unknown colorless solution turns blue when metal green is added and it also turns blue when congo red is added, Which range of ph values could the solution be? So the first thing you want to do is you want to make a chart with our indicators, the color change and the ph change. So you have the color change, the ph change and the indicators. And so the two indicators that we know from the question stem are metal green and congo red. You know that the color change for a methyl green is yellow to blue and the color change for congo red is blue to red. So the ph change for our method green according to our reference values in textbooks should be 0.2 to 1.8 and the ph change for congo red should be 3 to 5. And so we have to note that a solution with metal green is blue When the Ph is above 1.8. And we also know that a solution with Congo red is blue when the ph is less than three. So the possible range for the unknown solution. So our unknown solution range Must be between 1.8 and 3.0. And based on this, the best answer choice is going to be a 2-3. And with that we have our answer. I hope this helped and until next time