Question

In this experiment 2.0 mL of tert-butyl chloride (TBC) will be used. The density of TBC is 0.847 g/mL and its molar mass is 92.57 g/mol. (a) Calculate the weight and the number of moles of TBC to be used. (b) Calculate the number of moles of HCl that would be produced by the complete hydrolysis of the 2.0 mL of TBC. (c) Calculate the volume of 0.400 M NaOH solution required to neutralize the total amount of HCl produced by the hydrolysis reaction as calculated in (b) (d) Will a 50 mL buret contain sufficient of the above NaOH solution to neutralize the HCl produced when the hydrolysis reaction has reached 70% completion?

Answer 1

a. tert-butyl chloride (TBC) weight

=2 (ml)*0.847 (density)

=1.694 g ,

no of moles 0.0182 moles

=wt/mwt

=1.694/92.57

=0.0182 moles

b. reaction CH3)3C-Cl + H2O - (CH3)3C-OH+ HCl

molar mass 92.57 + 18 74.12 + 36.5

1.694 g ?

  

above equation shows 92.57 g produce 36.5 g of HCl

so 1.694 g ?

=1.694*36.5/92.57

=0.6679 g of HCl will produce.

0.6679/36.5

=0.01829 moles of HCl.

c. HCl+NaOH NaCl +H₂O

36.5 +40 58.5 +18

above reaction 1;1 required for neutralization 0.01829 moles required 0.1829 moles NaOH

so 0.01829*40 =0.7316 g of NaOH(100% but we have 0.4 M NaOH)

1 M contain 40 g of NaOH in 1000 ml

0.4 M contain 16 g NaOH in 1000 ml

we require 0.7316 g

so 0.7316*1000/16

=45.72 ml contain 0.7316 g of NaOH.

so 0.4 M NaOH solution 45.72 ml require to neutralize the HCl

d. if consider 100% reaction required 45.72 ml

45.72*0.7

=32.00 ml

when 70% reaction 32.0 ml of 0.4M NaOH solution.

so the 50 ml buret contain more 32 ml 0.4 m NaOH, this is sufficient to neutalize HCl.