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why A? (1 Viewer)
- Thread starter kkk579
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kkk579
hello
bump
kkk579
hello
bump
Sodium hydroxide acts as a base in solution. So imagine, when the indicator is in a basic solution, the protons/H+ in H2Z are going to be 'attracted' to the base, creating that ionisation seen in the question. Or consider it in terms of Le Chatelier's principle - if we add more basic solution to the 1st equation, it will shift towards the RHS with acidic H3O+ to counteract this. Same thing happens then in the 2nd equation, so the equilibrium is eventually shifted towards the blue colour in basic solution.
Same idea applies to HCl, just the equilibrium is shifting to the left in both equations. The more acid we add, the more the equation shifts to the left to counteract this/the more acid is used up. So, you end up with the red solution.
Finally, sodium acetate is only slightly basic (compared to NaOH, which has a much higher pH at the same concentration). This means that the equilibrium shifts to the right, but not as much as with NaOH. So, you kind of end up in between yellow and blue -> green.
A big part of this question is just kind of knowing how acidic/basic different solutions are relative to each other. E.g., we know that HCl is more acidic than ammonium chloride, hence the answer can't be B.
Same idea applies to HCl, just the equilibrium is shifting to the left in both equations. The more acid we add, the more the equation shifts to the left to counteract this/the more acid is used up. So, you end up with the red solution.
Finally, sodium acetate is only slightly basic (compared to NaOH, which has a much higher pH at the same concentration). This means that the equilibrium shifts to the right, but not as much as with NaOH. So, you kind of end up in between yellow and blue -> green.
A big part of this question is just kind of knowing how acidic/basic different solutions are relative to each other. E.g., we know that HCl is more acidic than ammonium chloride, hence the answer can't be B.
kkk579
hello
Yeah i get this, but then what would happen? Do the 2 colours merge or something? Or is it like a progression, where it first turns red to yellow then yellow to blue? I was unsure as to how the equations actually work togetherSodium hydroxide acts as a base in solution. So imagine, when the indicator is in a basic solution, the protons/H+ in H2Z are going to be 'attracted' to the base, creating that ionisation seen in the question. Or consider it in terms of Le Chatelier's principle - if we add more basic solution to the 1st equation, it will shift towards the RHS with acidic H3O+ to counteract this. Same thing happens then in the 2nd equation, so the equilibrium is eventually shifted towards the blue colour in basic solution.