Classify each of these reactions. Pb ( NO 3 ) 2 ( aq ) + 2 KCl ( aq ) ⟶ PbCl 2 ( s ) + 2 KNO 3 ( aq ) C 2 H 4 ( g ) + 3 O 2 ( g ) ⟶ 2 CO 2 ( g ) + 2 H 2 O ( l ) Cu ( s ) + FeCl 2 ( aq ) ⟶ Fe ( s ) + CuCl 2 ( aq ) 2 KOH ( aq ) + H 2 SO 4 ( aq ) ⟶ K 2 SO 4 ( aq ) + 2 H 2 O ( l )

For a: The reaction is a double displacement reaction.

For b: The reaction is a combustion reaction.

For c: The reaction is a single displacement reaction.

For d: The reaction is a neutralization reaction.

Explanation:

For the given equations:

Equation 1:

This reaction is an example of double displacement reaction because here exchange of ions takes place.

Equation 2:

This reaction is an example of combustion reaction because here hydrocarbon is reacting with oxygen gas to produce carbon dioxide gas and water molecule

Equation 3:

This reaction is an example of single displacement reaction because here more reactive element displaces a less reactive element.

Equation 4:

This reaction is an example of neutralization reaction because here a base reacts with an acid to produce a salt and water molecule

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

i believe that it is a exoplanet