84. A salution of a substance x is used of a
for
il Name the sulsstance 'x' and the
white kashing
write its farmula
il y Write the reaction the substance
la' named in il above with water.
of
dne

Following are the answer to this question:

Explanation:

(1) Calcium oxide (CaO) is also referred to as quicklime. It is the solution for the substance used for whitewashing.  

Whenever it reacts with water () and absorbs carbon dioxide (), it then formed calcium carbonate (), which produced a hard laminate on the walls, to first be whitened by the production of calcium hydroxide (CaOH).  

(2) Slackened lime or calcium hydroxide arises whenever the fast limestone reacts with water.

the answer is d.) potassium

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol