Question

How many moles are present in 4 gram of sodium hydroxide?

Answer 1

40 gram of mole is present

Answer 2

$\bf\huge\textbf{\underline{\underline{According\:to\:the\:Question}}}$

Molar mass of NaoH

= 23 + 16 + 1  

= 40g

40g of NaoH = 1 mole

$\bf\huge 1 \:gram\: of\: NaoH = \dfrac{1}{40}mole$

Therefore

4 gram of NaoH  

$\bf\huge = \dfrac{1}{40}\times 4\:mole$

= 0.1 mole