urgent need help with the q attached below. (1 Viewer)

[medaspirant]

any help in this q is appreciated

 

[LennonTheLemon]

What is your question though?

If you are trying to solve for x, do that using the quadratic equation.

If you are wondering what total [H+] is, it should be 0.0750M + the value of x. If you think about it logically (and this is a common mistake), your total wouldn't be 0.0750M from the first ionisation + (0.0750M + x) from the second ionisation, as the second ionisation can't release more H+ than the first, complete ionisation.

 

[LennonTheLemon]

Also made the assumption that your working out is correct and solved for x, getting 0.0245... but when you plug that value of x back into the Ka2 expression, you don't get the Ka2 value of 0.012 (this is a sanity check you can do). Looks like something has fallen apart lol.

 

[LennonTheLemon]

On the top line of your Ka2 expression you made a mistake and wrote 0.75x instead of 0.075x, so maybe just restart on a blank piece of paper. gl

 

[username_2]

any help in this q is appreciated

You forgot to include the 0.75x tern in your final quadratic.

 

[medaspirant]

On the top line of your Ka2 expression you made a mistake and wrote 0.75x instead of 0.075x, so maybe just restart on a blank piece of paper. gl

thx m8 did that and used ur above comments and i got correct answer now