Question

Write the molecular formula of ferric oxide and calcium hydroxide by criss-cross method ​

Answer 1

Ferric Oxide:-

$\setlength{\unitlength}{1cm}\begin{picture}(0,0)\thicklines\put(0,3){\bf Fe}\put(0,0){\bf -3}\put(4,3){\sf O}\put(4,0){\bf -2}\put(0.2,2.9){\vector(4,-3){3.5}}\put(3.8,2.9){\vector(-4,-3){3.5}}\end{picture}$

$\\ \sf\longmapsto Fe_2O_3$

Calcium Hydroxide:-

$\setlength{\unitlength}{1cm}\begin{picture}(0,0)\thicklines\put(0,3){\bf Ca}\put(0,0){\bf 2}\put(4,3){\sf OH}\put(4,0){\bf -1}\put(0.2,2.9){\vector(4,-3){3.5}}\put(3.8,2.9){\vector(-4,-3){3.5}}\end{picture}$

$\\ \sf\longmapsto Ca(OH)_2$