Addition of phenolphthalein to an unknown colorless solution does not cause a color change. The addition of bromthymol blue to the same solution leads to a yellow color. (b) Which of the following can you establish about the solution: (i) A minimum pH, (ii) A maximum pH, or (iii) A specific range of pH values?

Video transcript

Hello everyone today. We are being given the following problem. A 300 mL solution was formulated by dissolving 5.5 g of sodium chloride. 2.35 g of sodium hydroxide and 3.41 g of sodium bromide in water and diluting to the specified volume, calculate the concentration in molar itty of the ions present in the solution. So the first thing that we must do is you must calculate the polarity of each solution. So calculate the polarity of each solution. So first we're going to start off with N A C L. Or sodium chloride. So with in a cl, what we're going to do is we're going to start off with our given which is our 5.5 g of NACL. And we're going to place that over our 300 middle leaders. We are then going to do a couple of conversion factors with one being the conversion factor of grams to moles. So we're gonna say that one mole of N A C l is equal to 58.44 g of n A C L. Or the molar mass of sodium chloride. And then we want to get rid of this middle leaders here so we can use the conversion factor that one. Middle leader is equal to 10 to the negative third leaders When all of our units cancel out, we were left with 0. polarity. We are going to complete this process for the other two concentrations. So we have the concentration of our sodium hydroxide here. And that is going to be once again the mass, which is 2.35 g of sodium hydroxide Over our 300 middle leaders, We're gonna do the conversion factor that one Mole of sodium hydroxide is equal to the molar mass, which is 39 . g of sodium hydroxide. And then we want to get rid of this middle leader. So we're gonna use a conversion factor that one. Middle leader is equal to 10 to the negative third leaders. As before our units will cancel out and we will be left with 0.1958 Mueller. And last but not least we have the concentration of sodium bromide. So we take the mass 3.41 g of sodium bromine Over 300 ml. We use the conversion factor that one mole of sodium bromide is equal to 102.894 g of sodium bromide. And then lastly we used the conversion factor that one. Middle leaders equal to 10 to the negative. Their leaders. When our units cancel out, we are left with 0.1105 moller of sodium bromide. You're going to attach the units for the other substances as well. To avoid confusion. So once we have the clarity of each solution, we can then calculate the malaria of each ion so that we have the clarity of the solution. We can calculate the polarity of each ion. So for sodium It is present in each and every one of these. And so we're going to multiply all of their moralities together. So that's the .31 37 plus the 0.1958 polarity plus the 0.11 +05 polarity to give us 0.6 to zero polarity of sodium plus. And so that's going to be similarity of the sodium ion. For the chlorine ion. It's going to be simply the 0.3 14 which is taken from the majority of our sodium and subtracting it by the polarity of our In a cl which is 0.3137 to give us zero point 314 Polarity. We're going to do the same for our hydroxide and our bromide for high hydroxide, It's going to be 0.6-0 Moeller subtracted by the clarity that we got, which is 0.1958 To us .96. And the same thing for bromide which will result in us getting point 111 Mueller of bromine with that. We've answered the question overall. I hope this helped until next time