The acid ionization equilibrium for the weak acid HF is represented by the equation below. To prepare a buffer with a pH=3.50 , a student needs to mix 250.mL of 0.100MHF and 250.mL of 0.100MKF . If the student mistakenly mixes 250.mL of 0.0500MHF and 250.mL of 0.0500MKF , which of the following is the result of this error? *

16

explanation:

the marks go by 4s

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2