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Which or these equations is balanced H2SO4 + 2Al > Al2(SO4)3 + H2 or 2KCl + Pb(NO3)2 > 2KNO3 + PbCl2

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Balancing of chemical equation is essential because of the law of conservation of mass, which states that the mass of a system can not be created or removed.

The second equation is balanced


2KCl_(_a_q_) +Pb(NO_3)_2_(_a_q_) ==> 2KNO_3_(-a_q_) + PbCl_2(_a_q_)

This is because the number of elements of each atom in the product side equal the number of elements of each atom on the reactant side.

The first equation is not balanced


H_2SO_4 _(_a_q) + 2Al_(_s_) ==> Al(SO_4)_3_(_a_q_) + H_2_(_g_)

This is because there is 1 molecule of
SO_4^(-2) on reactant side as compared to 3 molecules of
SO_4^(-2)

To balance the equation we add a coefficient of 3 on sulphuric acid (
H_2SO_4) and a coefficient of 3 on hydrogen (
H_2)


3H_2SO_4_(_a_q_) + 2Al_(_s_) ==> Al(SO_4)_3_(_a_q_) + 3H_2_(_g_)

User Matt Haberland
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