chemistry question

madah123 · **Joined:** Dec 2007 **Posts:** 176 **Location:** kuwait

i am wondering if anyone knows why Hydrangea isnt an accurate indicator for an Acid-base titration my teacher game us this question and it isnt on the book so any one knows?

MrJoey · **Posted:** Fri Jan 30, 2009 6:40 pm

Are you sure you got the right word? Hydrangea is a flower.

madah123 · **Joined:** Dec 2007 **Posts:** 176 **Location:** kuwait

well i am not sure if it's Hydrangea but it is aflower that if you put it in an acid it becomes red and if you put it in abase it becomes blue if you put it in aneutral it become purpil i am not sure of its name in english.
our teacher gave us this question when we were studying indicators of Acid-base titration .

chickenfeather · **Posted:** Fri Jan 30, 2009 7:11 pm

http://en.wikipedia.org/wiki/Hydrangea

wiki is your friend.

SM-Count · **Joined:** Jan 2008 **Posts:** 2761 **Location:** /wave

Because by the time you realize you've neutralized the unknown and it's time to do calculations for 'M' you'll be dead and have over poured your known so much that you will be off the literature value by more than 100%?

Also, it's transition zone, if the google link is right, is 6.5-7.0. It's colors go red->purple->blue, not only is that difficult to read, and time consuming >.>, 6.5-7.0 is better for biochem experiments and not acid-base titrations because it's range isn't suitable. That doesn't have too much to do with accuracy, just sensitivity.

CrimsonNuker · **Joined:** Aug 2006 **Posts:** 13791 **Location:**

SM-Count wrote:

Because by the time you realize you've neutralized the unknown and it's time to do calculations for 'M' you'll be dead and have over poured your known so much that you will be off the literature value by more than 100%?

Also, it's transition zone, if the google link is right, is 6.5-7.0. It's colors go red->purple->blue, not only is that difficult to read, and time consuming >.>, 6.5-7.0 is better for biochem experiments and not acid-base titrations because it's range isn't suitable. That doesn't have too much to do with accuracy, just sensitivity.

Now thats some advanced shit

Kirkaldi · **Joined:** Jul 2008 **Posts:** 3083 **Location:** nyc

SM-Count wrote:

Because by the time you realize you've neutralized the unknown and it's time to do calculations for 'M' you'll be dead and have over poured your known so much that you will be off the literature value by more than 100%?

Also, it's transition zone, if the google link is right, is 6.5-7.0. It's colors go red->purple->blue, not only is that difficult to read, and time consuming >.>, 6.5-7.0 is better for biochem experiments and not acid-base titrations because it's range isn't suitable. That doesn't have too much to do with accuracy, just sensitivity.

lul wut

ThiefzV2 · **Joined:** Jan 2007 **Posts:** 566 **Location:**

Kirkaldi wrote:

SM-Count wrote:

Because by the time you realize you've neutralized the unknown and it's time to do calculations for 'M' you'll be dead and have over poured your known so much that you will be off the literature value by more than 100%?

Also, it's transition zone, if the google link is right, is 6.5-7.0. It's colors go red->purple->blue, not only is that difficult to read, and time consuming >.>, 6.5-7.0 is better for biochem experiments and not acid-base titrations because it's range isn't suitable. That doesn't have too much to do with accuracy, just sensitivity.

lul wut

he google and rephrase a paragraph cuz it doesnt even answer the OP question lol

StealMySoda · **Joined:** Sep 2006 **Posts:** 5245 **Location:**

What he's saying is that...basically it takes WAY too long to change color.
Litmus
pH
Universal indicator

Are all instant indicators.

Who the **** wants to sit around for ages for a flower to change colors.

dom · **Posted:** Sat Jan 31, 2009 4:13 am

StealMySoda wrote:

What he's saying is that...basically it takes WAY too long to change color.
Litmus
pH
Universal indicator

Are all instant indicators.

Who the **** wants to sit around for ages for a flower to change colors.

The Japanese

madah123 · **Joined:** Dec 2007 **Posts:** 176 **Location:** kuwait

SM-Count wrote:

Because by the time you realize you've neutralized the unknown and it's time to do calculations for 'M' you'll be dead and have over poured your known so much that you will be off the literature value by more than 100%?

Also, it's transition zone, if the google link is right, is 6.5-7.0. It's colors go red->purple->blue, not only is that difficult to read, and time consuming >.>, 6.5-7.0 is better for biochem experiments and not acid-base titrations because it's range isn't suitable. That doesn't have too much to do with accuracy, just sensitivity.

so we will not know the drop that ends the titration?

takolin · **Joined:** Jan 2007 **Posts:** 4238 **Location:** Life

It comes down to this:

A good acid/base indicator changes colour with half a drop. Yes I learned to titrate with half drops.

The times it'll take for the flower to change colour, would take too long and I doubt it's sensitive enough.
Thus you'd have to wait like 15-30 minutes after each drop to see if the colour changes.

madah123 · **Joined:** Dec 2007 **Posts:** 176 **Location:** kuwait

oh I see thanks for the answers.

ThiefzV2 · **Joined:** Jan 2007 **Posts:** 566 **Location:**

StealMySoda wrote:

Who the **** wants to sit around for ages for a flower to change colors.

but i do

the OP question stated why it isnt an accurate ph indicator.

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