Answer:
Carbon dioxide reacts with limewater (a solution of calcium hydroxide, Ca(OH) 2), to form a white precipitate (appears milky) of calcium carbonate, CaCO 3.
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Molality is defined as 1 mole of a solute in 1 kg of solvent.
Molality=

Number of moles of solute, n=

Given mass of the nitrobenzene=0.2 g
Molar mass of the substance= 123.06 g mol⁻¹
Number of moles of nitrobenzene,

Number of moles of nitrobenzene, n= 0.0016 mol
Mass of 10.9 g of naphthalene in kg=0.0109

Molality= 0.146 m
Answer : The time passed in years is 
Explanation :
Half-life = 5730 years
First we have to calculate the rate constant, we use the formula :



Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = 
t = time passed by the sample = ?
a = let initial amount of the reactant = X g
a - x = amount left after decay process = 
Now put all the given values in above equation, we get


Therefore, the time passed in years is 
Answer:
H₂CO₃→H₂O + CO₂
Exphlanation:
Soda is carbonated water. It contains carbon dioxide dissolved in water , which is carbonic acid. On opening the soda, the carbonic acid undergoes the reverse reaction and releases carbon dioxide in the air . The soda is thus left with just water and loses it's fizz.