Calculating the pH of Gastric Juice from a Frog

[jena]

Hi,

My Question:

Upon evisceration, it was discovered that the frog had died due to acid ingestion. 10mL of gastric juice was found in its stomach required 7.2mL of 0.1 M NaOh for neutralization. Calculate the pH of its gastric juice.

I'm confused, how would I approach this problem.

Thank You

 

[amcavoy]

Hi,

My Question:

Upon evisceration, it was discovered that the frog had died due to acid ingestion. 10mL of gastric juice was found in its stomach required 7.2mL of 0.1 M NaOh for neutralization. Calculate the pH of its gastric juice.

I'm confused, how would I approach this problem.

Thank You

Well first you might want to find the pH of the NaOH solution. Also, what have you tried?

Alex

 

[jena]

So it would be like this

poH=log[H]
poh=-log[0.1]
poH=1

and

ph+poH=14
ph+1=14
ph=13

Is this correct

thank you

 

[amcavoy]

So it would be like this

poH=log[H]
poh=-log[0.1]
poH=1

and

ph+poH=14
ph+1=14
ph=13

Is this correct

thank you

That looks good for the pH of the NaOH solution. Now, you want to find the pH of the gastric acid. Do you know how to do so from here?

Alex

 

[jena]

No , I still don't know what to do. Also what do I do with the mL's

Thank You

 

[Borek]

No need for pOH.

Calculate from simple stoichiometry amount of HCl in the gastric juice, then its concentration - once you know concentration of HCl pH calculation should be a breeze.

 

[jena]

Sorry to reply so late, so I would first find the concentration like so,

M1V1=M2V2

and then use the concentration to find the pH of the acid using this equation

ph=-log(H+)

Is that the correct method?

Thank You

 

[Borek]

Show what you did as your answer about using M1V1=M2V2 is ambiguous.

 

[P-man]

Wouldn't it help if you knew the formula of the gastric juice?

 

[Borek]

P-man - gastric juice contains mostly HCl.

 

[P-man]

Oh, sorry. I guess that's the stuff in your stomach?