Acid-Base question HELP!

OP

Original post by ElectronDonor

Are you kidding me multiple choice, is this a level

yes, do you know how to answer the question?

Reply 3

Original post by ahjinayo

yes, do you know how to answer the question?

Yes i do, you are so lucky, a levels must be a peace of cake now

Reply 4

Original post by ahjinayo

^{A mixture of 20cm3 of 1.0moldm-3 of HCl and 10cm3 of 1.0moldm-3 of NaOH .}^{is the PH}^{a) 0}^{b) 0.30}^{c) 0.48}^{d) 7}

^{why is the answer c. I saw that somebody else answered this question on here but I don't understand the way they have worked it out! can anybody help please?}

^{thank you}

What is the whole question

Reply 5

OP

Original post by ElectronDonor

What is the whole question

that is the whole question, you have to work out the Ph from the information given which I included in my 1st comment.

Reply 6

Original post by ahjinayo

that is the whole question, you have to work out the Ph from the information given which I included in my 1st comment.

Have you done logs

Reply 7

OP

Original post by ElectronDonor

Have you done logs

yes

Reply 8

OP

Original post by ElectronDonor

Have you done logs

I know that the 1st thing I have to do is to work out the moles.

moles of hcl= 20/1000x1.0= 0.02
moles of naoh= 10/1000x1.0=0.01

where do I go from there ?

Reply 9

Original post by ahjinayo

I know that the 1st thing I have to do is to work out the moles.

moles of hcl= 20/1000x1.0= 0.02
moles of naoh= 10/1000x1.0=0.01

where do I go from there ?

Work out pH of just hcl and naoh

Reply 10

OP

Original post by ElectronDonor

Work out pH of just hcl and naoh

that doesn't give me the correct answer if I just work out the Ph's

Reply 11

OP

Original post by ElectronDonor

Work out pH of just hcl and naoh

Can you explain to me how to work out this problem please?

Reply 12

AlexSaxton

1

Subtract the no. Of moles of NaOH from HCL to get Xs H+. Then divide by your new volume (vol HCL + vol NaOH) and log that

Posted from TSR Mobile

Reply 13

OP

Original post by AlexSaxton

Subtract the no. Of moles of NaOH from HCL to get Xs H+. Then divide by your new volume (vol HCL + vol NaOH) and log that

Posted from TSR Mobile

why do you have to subtract the moles of naoh from hcl?

Reply 14

AlexSaxton

1

Because when HCL and NaOH react they react one to one and if there's more of one than the other, the one in excess will have some left over depending on the amount it has been used up

Posted from TSR Mobile

Reply 15