Tag: practical work

Questions Related to practical work

The reaction between copper oxide and hydrochloric acid is a:

distinguish between black copper oxide and black manganese dioxide practical work chemistry

  1. acid base reaction

  2. replacement reaction

  3. combustion reaction

  4. both $A$ and $B$

Show answer
Correct Option: D
Explanation:

The reaction copper oxide and hydrochloric acid is an acid-base reaction due to the hydrogen and oxygen found in the reactants, then forming water ($H _2O$). This is also a replacement reaction because the copper ($Cu$) is "swapping out" with the hydrogen ($H$) creating two different molecules.

A manganese dioxide battery is treated with conc. HCl, what are the products?

distinguish between black copper oxide and black manganese dioxide practical work chemistry

  1. $MnCl _2$

  2. $H _2O$

  3. $Cl _2$

  4. All of above

Show answer
Correct Option: D
Explanation:

$MnO _2 + 4 HCl \rightarrow MnCl _2 + Cl _2 + 2 H _2O$

Write the ionic equation for reaction between manganese dioxide and hydrochloric acid.

distinguish between black copper oxide and black manganese dioxide practical work chemistry

  1. $MnO _2(s)+ 2Cl^{-}(aq) \rightarrow Mn^{2+}(aq) + Cl _2(g) + 2H _2O(l)$

  2. $MnO _2{(s)} + 4H^{+}{(aq)} + 2Cl^{-}{(aq)} \rightarrow Mn^{2+}{(aq)} + Cl _2{(g)} + 2H _2O{(l)}$

  3. $MnO _2{(s)} + 3H^{+}{(aq)} + 2Cl^{-}{(aq)} \rightarrow Mn^{2+}{(aq)} + Cl _2{(g)} + 2H _2O{(l)}$

  4. $MnO _2{(s)} + 4H^{+}{(aq)} + 2Cl^{-}{(aq)} \rightarrow Mn^{2+}{(aq)} + Cl{(g)} + 2H _2O({l})$

Show answer
Correct Option: B
Explanation:

$MnO _2{(s)} + 4H^{+}{(aq)} + 2Cl^{-}{(aq)} \rightarrow Mn^{2+}{(aq)} + Cl _2{(g)} + 2H _2O{(l)}$

The salt formed on reaction of copper oxide with hydrochloric acid is :

distinguish between black copper oxide and black manganese dioxide practical work chemistry

  1. Cuprous chloride

  2. Cupric chloride

  3. Both formed in $1:2$ ratio

  4. Both formed in $1:3$ ratio

Show answer
Correct Option: B
Explanation:

copper oxide $+$ hydrochloric acid $\rightarrow $ copper chloride $+$ water

 $CuO+2HCl \rightarrow  CuCl _{2}+H _{2}O$