Question

1. __c₄h₈ + o₂ → co₂ + __h₂o type of reaction: combustion
2. __hcl + naoh → h₂o + __nacl type of reaction: double rep

Explanation:

Step1: Balance C in reaction 9

Set coefficient of $\text{CO}_2$ to 4 (matches 4 C in $\text{C}_4\text{H}_8$).
$\text{C}_4\text{H}_8 + \text{O}_2
ightarrow 4\text{CO}_2 + \text{H}_2\text{O}$

Step2: Balance H in reaction 9

Set coefficient of $\text{H}_2\text{O}$ to 4 (8 H in $\text{C}_4\text{H}_8$ → $4\times2$ H).
$\text{C}_4\text{H}_8 + \text{O}_2
ightarrow 4\text{CO}_2 + 4\text{H}_2\text{O}$

Step3: Balance O in reaction 9

Total O on right: $4\times2 + 4\times1 = 12$ → O₂ coefficient = 6.
$1\text{C}_4\text{H}_8 + 6\text{O}_2
ightarrow 4\text{CO}_2 + 4\text{H}_2\text{O}$

Step4: Balance reaction 10

Count atoms: 1 H,1 Cl,1 Na,1 O on left → match right.
$1\text{HCl} + 1\text{NaOH}
ightarrow 1\text{H}_2\text{O} + 1\text{NaCl}$

Answer:

1. Coefficients: 1, 6, 4, 4; Reaction type: Combustion
2. Coefficients: 1, 1, 1, 1; Reaction type: Double Replacement (Neutralization)