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Chemical Reactions — CHEMISTRY STD 8 — Question

ICSE BoardEnglish MediumSTD 8CHEMISTRYChemical Reactions2 Marks
Question
Differentiate between $–$
$(a)$ Direct combination reaction $\&$ a decomposition reaction
$(b)$ Displacement reaction $\&$ a neutralization reaction.
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Answer

$(a)$ Direct combination: "Is a reaction in which two elements ' or compound combine to give one new compound."
$C + \ce{O_2 \rightarrow CO_2}$
Decomposition reaction: "A chemical compound $($breaks up$)$ decomposes into two or more simpler substances."
Copper carbonate $\rightarrow$ Copper oxide + carbon dioxide
$\ce{CuCO_3 \rightarrow CuO}+\ce{CO_2}$
$(b)$ Displacement reaction : “A chemical reaction in which an element displaces the element from a solution of its compound.”
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In a activitiy series of metals, an element placed higher displaces the element placed below it.
Here $Zn$ is placed above $Cu$ in activity series of metal and is more reactive than copper has displaced $Cu$ from copper sulphate.
Neutralization reaction :
“A reaction between an acid and a base to form salt and water is called neutralization reaction.”
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