Question

Balance the equation and identify the type of reaction for ? P4(s) + ? Ca(s) → ? Ca3P2(s). 1. 2; 6; 2 — decomposition 2. 2; 6; 2 — displacement 3. 1; 6; 2 — displacement 4. 1; 6; 2 — synthesis 5. 2; 6; 2 — synthesis 6. 1; 6; 2 — decomposition

Answer 1

Answer:

4. 1; 6; 2 — synthesis

Explanation:

Decomposition reaction is defined as the reaction in which a single large substance breaks down into two or more smaller substances.

$AB\rightarrow A+B$

Single displacement reaction is defined as the reaction in which more reactive element displaces a less reactive element from its chemical reaction.

The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.

$A+BC\rightarrow AC+B$

Synthesis reaction is defined as the reaction in which smaller substances combine in their elemental state to form a larger substance.

$A+B\rightarrow AB$

The unbalanced combustion reaction is shown below as:-

$P_4+Ca\rightarrow Ca_3P_2$

On the left hand side,  

There are 4 phosphorus atoms and 1 calcium atom

On the right hand side,  

There are 2 phosphorus atoms and 3 calcium atoms

Thus,  

Right side, $Ca_3P_2$ must be multiplied by 2 to balance phosphorus.

Left side, $Ca$ is multiplied by 6 so to balance the whole reaction.

Thus, the balanced reaction is:-

$P_4+6Ca\rightarrow 2Ca_3P_2$

Thus, answer:- 4. 1; 6; 2 — synthesis