Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute $H_2SO_4$.
Hydrogen gas is evolved when dilute hydrochloric acid is added to a reactive metal.
When iron reacts with dilute $H _{2} SO _{4}$ iron $(II)$ sulphate with the evolution of hydrogen gas is formed.
$Fe _{( s )}+ H _{2} SO _{4( aq )} \longrightarrow FeSO _{4( aq )}+ H _{2( g )}$
Which of the following methods is suitable for preventing an iron frying pan from rusting ?
A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?
What type of oxides are formed when non-metals combine with oxygen?
Give reasons : Platinum, gold and silver are used to make jewellery.
Samples of four metals $A$, $B$, $C$ and $D$ were taken and added to the following solution one by one. The results obtained have been tabulated as follows.
Metal | Iron $(II)$ sulphate | Cooper $(II)$ sulphate | zinc sulphate | Silver nitrate |
$A.$ | No reaction | Displacement | ||
$B.$ | Displacement | No reaction | ||
$C.$ | No reaction | No reaction | No reaction | Displacement |
$D.$ | No reaction | No reaction | No reaction | No reaction |
Use the Table above to answer the following questions about metals $A$, $B$, $C$ and $D$.
$(i)$ Which is the most reactive metal ?
$(ii)$ What would you observe if $B$ is added to a solution of Copper $(II)$ sulphate ?
$(iii)$ Arrange the metals $A$, $B$, $C$ and $D$ in the order of decreasing reactivity.