Question

$$ \text{nabr}+\text{caf}_2 \to \text{naf}+\text{cabr}_2 $$
what coefficients are needed to balance the chemical equation?
a 1,1,1,1
b 1,2,1,2
c 1,2,2,1
d 2,1,2,1

Explanation:

Step1: Count atoms on both sides

On the left - hand side: \(1\) \(Na\), \(1\) \(Br\), \(1\) \(Ca\), \(2\) \(F\). On the right - hand side: \(1\) \(Na\), \(2\) \(Br\), \(1\) \(Ca\), \(1\) \(F\).

Step2: Balance bromine atoms

To balance \(Br\) atoms, put a coefficient of \(2\) in front of \(NaBr\). The equation becomes \(2NaBr+CaF_{2}\to NaF + CaBr_{2}\). Now, on the left - hand side: \(2\) \(Na\), \(2\) \(Br\), \(1\) \(Ca\), \(2\) \(F\). On the right - hand side: \(1\) \(Na\), \(2\) \(Br\), \(1\) \(Ca\), \(1\) \(F\).

Step3: Balance sodium and fluorine atoms

Put a coefficient of \(2\) in front of \(NaF\). The balanced equation is \(2NaBr + CaF_{2}\to2NaF+CaBr_{2}\).

Answer:

D. \(2,1,2,1\)