Question

h₂ + o₂ => h₂o₂
na + o₂ => na₂o
al(oh)₃ + h₂co₃ => al₂(co₃)₃ + h₂o
al + s₈ => al₂s₃
cs + n₂ => cs₃n
mg + cl₂ => mgcl₂
rb + rbno₃ => rb₂o + n₂
c₆h₆ + o₂ => co₂ + h₂o
n₂ + h₂ => nh₃

Explanation:

Step1: Balance the first equation

$2H_2 + O_2
ightarrow 2H_2O$ (the given $H_2 + O_2
ightarrow H_2O_2$ is incorrect for normal water - formation, the correct one for water is balanced as above)

Step2: Balance the second equation

$4Na+O_2
ightarrow 2Na_2O$

Step3: Balance the third equation

$2Al(OH)_3 + 3H_2CO_3
ightarrow Al_2(CO_3)_3+6H_2O$

Step4: Balance the fourth equation

$16Al + 3S_8
ightarrow 8Al_2S_3$

Step5: Balance the fifth equation

$6Cs + N_2
ightarrow 2Cs_3N$

Step6: Balance the sixth equation

$Mg + Cl_2
ightarrow MgCl_2$ (already balanced)

Step7: Balance the seventh equation

$10Rb + 2RbNO_3
ightarrow 6Rb_2O+N_2$

Step8: Balance the eighth equation

$2C_6H_6 + 15O_2
ightarrow 12CO_2+6H_2O$

Step9: Balance the ninth equation

$N_2 + 3H_2
ightarrow 2NH_3$

Answer:

Balanced equations:
$2H_2 + O_2
ightarrow 2H_2O$
$4Na+O_2
ightarrow 2Na_2O$
$2Al(OH)_3 + 3H_2CO_3
ightarrow Al_2(CO_3)_3+6H_2O$
$16Al + 3S_8
ightarrow 8Al_2S_3$
$6Cs + N_2
ightarrow 2Cs_3N$
$Mg + Cl_2
ightarrow MgCl_2$
$10Rb + 2RbNO_3
ightarrow 6Rb_2O+N_2$
$2C_6H_6 + 15O_2
ightarrow 12CO_2+6H_2O$
$N_2 + 3H_2
ightarrow 2NH_3$