Question

What volume, in liters, of 1.00 M KOH solution should be added to a 0.118 L solution containing 10.32 g of glutamic acid hydrochloride (Glu, FW = 183.59 g/mol; pKa1 = 2.23, pKa2 = 4.42, pKa3 = 9.95) to get to pH 10.31?

Answer #1

Moles of glutamic acid HCl present = mass/MW = 10.32/183.59 = 0.0562 moles

Since glutamic acid HCl is a weak acid, only its first dissociation is significant. Thus we will consider only the pKa1 value, because the other two dissociations will be insignificant.

Assume the volume of KOH taken as 'x' Liters.

Thus, moles of KOH taken = Volume*Molarity = x*1 = x moles

When 'x' moles KOH are added, 'x' moles of glutamic acid HCl react with them to form 'x' moles of salt.

Thus, moles of salt formed = x

Moles of acid left = 0.0562 - x

According to Henderson-Hasselbach equation,

pH = pKa + log(moles of salt/moles of acid)

10.31 = 2.23 + log(x/0.0562-x)

Solving, we get : **x = 0.0562 L
approximately**

What volume, in liters, of 1.03 M KOH solution should be added
to a 0.110 L solution containing 10.21 g of glutamic acid
hydrochloride (Glu, FW= 183.59 g/mol: pKa1= 2.23, pKa2= 4.42, pKa3=
9.95) to get to pH 10.24?.... but whenever i did it the way
provided by a different user and got an answer of .036 L it said
....."Incorrect. You did not account for the amount of KOH needed
to move glutamic acid through its first two acid...

How many milliliters of 1.00 M KOH should be added to 100 mL of
solution containing 10.0 g of histidine hydrochloride [His*HCl =
(HisH+)(Cl-), FM 191.62] to get a pH of 9.30?

How many milliliters of 1.72 M KOH should be added to
100. mL of solution containing 10.0 g of histidine hydrochloride
(His·HCl, FM 191.62) to get a pH of 9.30? pKa=9.28

Calculate the volume (in mL) of a 0.790 M KOH solution that
should be added to 5.250 g of HEPES (MW=238.306 g/mol, pKa = 7.56)
to give a pH of 7.86.

Calculate the volume (in mL) of a 0.620 M KOH solution that
should be added to 5.500 g of HEPES (MW=238.306 g/mol, pKa = 7.56)
to give a pH of 7.50.

Calculate the volume (in mL) of a 0.360 M KOH solution that
should be added to 4.500 g of HEPES (MW=238.306 g/mol, pKa = 7.56)
to give a pH of 7.50.

Calculate the volume (in mL) of a 0.700 M KOH solution that
should be added to 4.500 g of HEPES (MW=238.306 g/mol, pKa = 7.56)
to give a pH of 7.76.

Calculate the volume (in mL) of a 0.740 M KOH solution that
should be added to 5.500 g of HEPES (MW=238.306 g/mol, pKa = 7.56)
to give a pH of 7.50.

Calculate the volume (in mL) of a 0.360 M KOH solution that
should be added to 4.500 g of HEPES (MW=238.306 g/mol, pKa = 7.56)
to give a pH of 7.60.

Calculate the volume (in mL) of a 0.520 M KOH solution that
should be added to 6.000 g of HEPES (MW=238.306 g/mol, pKa = 7.56)
to give a pH of 7.58.

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 22 minutes ago

asked 49 minutes ago

asked 49 minutes ago

asked 2 hours ago

asked 2 hours ago

asked 3 hours ago

asked 3 hours ago

asked 4 hours ago

asked 4 hours ago

asked 5 hours ago

asked 5 hours ago

asked 5 hours ago