• Best of luck to the class of 2024 for their HSC exams. You got this!
    Let us know your thoughts on the HSC exams here
  • YOU can help the next generation of students in the community!
    Share your trial papers and notes on our Notes & Resources page
MedVision ad

titration calculation quesion (1 Viewer)

karen88

Radioactive Queen
Joined
Jun 21, 2004
Messages
197
Location
Sydney
Gender
Female
HSC
2005
i have problems with this question.... could anyone help me?

A household cleaning agent contains a weak baseof general formula NaX. 1.00g of this compound was dissolved in 100.00mL of water. A 20.0 mL sample of the solution was titrated with 0.1000 mol/L hydrochloric acid and required 24.4 mL of the acid for neutralisation.

what is the molar mass of this base?
 

LaCe

chillin, killin, illin
Joined
Jan 29, 2005
Messages
433
Location
Where am I?
Gender
Undisclosed
HSC
2005
i think this works

moles of HCl= 0.1*0.0244
= 0.00244 mol
moles of NaX= 0.00244 mol
0.00244 = mass/molar mass
molar mass = mass/moles
where mass is the original mass of NaX
 

Dreamerish*~

Love Addict - Nakashima
Joined
Jan 16, 2005
Messages
3,705
Gender
Female
HSC
2005
not fully sure.
i thought that strong bases generally have metals in the compound? Na should form a strong base.

NaX + HCl -> NaCl + HX ... [equation]

1.00g/100.0mL

20.0mL was titrated. therefore 1.00g x 0.2 = 0.2g of NaX was titrated.

24.4mL of HCl was required.
C = 0.1m L-1
= 0.00244m/24.4mL

the ratio of NaX to HCl is 1:1
therefore 0.00244m of NaX was used

0.00244m = 0.2g
1m = 81.967g

therefore molar mass of NaX = 81.967g
 
Last edited:

Pace_T

Active Member
Joined
Oct 21, 2004
Messages
1,784
Gender
Male
HSC
2005
.1 * 0.0244
= moles of HCL used

= moles of NaX used

mp = .2 g
(10g per litre *.02)

.'. .2g / 0.0244 = 81.97 = 82g per mol
(mp / moles = molar mass)
 

Pace_T

Active Member
Joined
Oct 21, 2004
Messages
1,784
Gender
Male
HSC
2005
1 g put in 100mL
1g per 0.1L

.'. therefore there is 10g of solid per litre
20ml is chosen

there is 50 20mL's in a 1 litre solution
so therefore 1 50th of the 10g in in the 20ml solution
1/50 * 10g = .2g

----------------
ok nevermind, i see you worked it out :)
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top