Answer: The correct answer is [tex]MgO+H_2O[/tex]
Explanation:
Synthesis reaction is defined as the reaction in which two smaller substances combine together to form a large single compound.
[tex]A+B\rightarrow AB[/tex]
For the given options:
Option 1: [tex]Cl_2+HBr[/tex]
These two combination produces hydrochloric acid and bromine gas. The reaction is known as single displacement reaction.
[tex]Cl_2+2HBr\rightarrow 2HCl+Br_2[/tex]
Option 2: [tex]Ca+H_2O[/tex]
These two combination produces calcium hydroxide and hydrogen gas. The reaction is known as single displacement reaction.
[tex]Ca+2H_2O\rightarrow Ca(OH)_2+H_2[/tex]
Option 3: [tex]MgO+H_2O[/tex]
These two combination produces magnesium hydroxide only. The reaction is known as synthesis reaction.
[tex]MgO+H_2O\rightarrow Mg(OH)2[/tex]
Option 4: [tex]C_2H_2+O_2[/tex]
These two combination produces carbon dioxide and water molecule. The reaction is known as combustion reaction.
[tex]2C_2H_2+5O_2\rightarrow 4CO_2+2H_2O[/tex]
From the above information, the correct answer is [tex]MgO+H_2O[/tex]
