In each of the combinations, predict the more electronegative element based on its position on the periodic table. Then look up the actual electronegativities. Circle the reaction pair that should
actually caust a reaction.
More
Combination Combination electronegative
A
B
element based on
position on table
Ba + Fe2-
Ba?- + Fe
Actual
Actual
electronegativity electronegativity
of element of element
a)
Ba =
Fe=
b)
)
Sn + Hg
Sn- + Hg
Sn =
Hg =
c)
)
Na + Mg2+
Na + Mg
Na=
Mg =
=
Zn + CO2-
Zn?- + Co
Zn =
Co=

c)

)

Na + Mg2+

Na + Mg

Na=

Mg =

=

Zn + CO2-

Zn?- + Co

Zn =

Co=

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