Chemistry
Define a displacement reaction with example. State why Zn displaces H2 from dil. H2SO4 but Cu does not.
Answer
A chemical reaction which takes place when an element [or radical] has replaced another element in a compound is known as Displacement reaction
It is represented as :
X + YZ ⟶ Y + XZ
e.g.,
Magnesium + Copper [II] sulphate ⟶ Magnesium sulphate + Copper
Mg + CuSO4 ⟶ MgSO4 + Cu
A more electropositive metal displaces a less electropositive metal from its aqueous solution. Therefore, zinc, being more electropositive, is placed above [H] in the activity series and displaces hydrogen from dilute sulphuric acid. Copper, being less electropositive, is placed below [H] in the electrochemical series and cannot displace hydrogen from sulphuric acid./p>
Related Questions
Give balanced equations for thermal decomposition of :
(a) lead carbonate
(b) lead nitrate
(c) ammonium dichromate
(d) mercury [II] oxide
(e) calcium hydroxide
Define a thermal dissociation reaction with a suitable example.
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With the help of balanced equations - show how precipitation reactions are used for identifying the positive radicals in three different salts, each having a different cation [positive ion].