Question

How many moles of ca(oh)2 are needed to neutralize 3moles of HCl

Answer 1

GiveN :-

• Calcium hydroxide reacts with Hydrochloric Acid.

To FinD :-

• How many moles of ca(oh)2 are needed to neutralize 3moles of HCl.

SolutioN :-

Given that Calcium hydroxide reacts with Hydrochloric Acid. We know that Calcium hydroxide is base and Hydrochloric Acid is a acid . So the reaction between them will be Neutralization Reaction or Double Displacement Reaction . They will react to give salt and water .

The word equation will be :-

$\boxed{\pink{\sf Calcium\ Hydroxide + Hydrochloric \ Acid \to Calcium\ chloride + Water }}$

The chemical equation will be :-

$\boxed{\pink{\sf Ca(OH)_2 + HCl \to CaCl_2+H_2O }}$

But we see here that the equation is not balanced. The number of Oxygen atoms on LHS is 2 but there is only one Oxygen atom in the RHS. Similarly there are 3 Hydrogen atoms in the LHS but there's only one Hydrogen atom in the RHS . Let's balance out the equation :-

Step 1: Multiplying 2 to HCl on LHS :-

$\boxed{\gray{\sf \pink{2} HCl + Ca(OH)_2\to CaCl_2 + H_2 O }}$

Step 2: Multiplying 2 to water on RHS :-

$\boxed{\gray{\sf \pink{2} HCl + Ca(OH)_2\to CaCl_2 + \pink{2}H_2 O }}$

Hence we balanced out the equation !!

$\rule{200}2$

★ Using Unitary Method :-

$\sf:\implies \textsf{ \gray{ 2 moles of HCl are neutralized by 1 mole of Calcium hydroxide . }}\\\\\implies\textsf{\gray{ 1 mole of HCl is neutralized by 1/2 moles of Calcium hydroxide .}}\\\\\implies\textsf{\gray{ Hence 3 moles of HCl is neutralized by }}\pink{\sf \dfrac{1}{2}\times 3 = \purple{1.5 \ moles }} .$