The answer is: II.The endpoint is recorded when the solution is dark red in color rather than light pink.
The endpoint is the point at which the indicator changes colour in a colourimetric titration and that is point when titration must stop.
Phenolphthalein is colorless in acidic solutions and pink in basic solutions. If this indicator change color to dark red, more base is added and endpoint is not accurate.
If the the acid is spilled before titration, that does not make endpoint wrong and molar mass can be calculated.
In this example we can take acetic acid as carboxylic acid; basic salt sodium acetate CH₃COONa is formed from the reaction between weak acid (in this example acetic acid CH₃COOH) and strong base (in this example sodium acetate NaOH).
Balanced chemical reaction of acetic acid and sodium hydroxide:
CH₃COOH(aq) + NaOH(aq) → CH₃COONa(aq) + H₂O(l).
Neutralization is is reaction in which an acid (in this example vinegar or acetic acid CH₃COOH) and a base react quantitatively with each other.
In easy words the connection between Reactants, Products and Limiting reactants is as follow,
Reactants and Products:
Reactants are the starting materials for the synthesis of final synthesized materials called as products.
Example:
CH₄ + 2 O₂ → CO₂ + 2 H₂O
In above reaction Methane (CH₄) and Oxygen (O₂) are the reactants while, CO₂ and H₂O are the products.
Reactants, Products and Limiting Reactants:
Considering the same example it is seen that for one mole of CO₂ two moles of O₂ are required to completely convert into CO₂ and H₂O. If either of the reactant is taken less than the required amount then it will act as a limiting reactant because it will consume first leaving the second reactant present in excess as compare to it. Hence, we can say that the limiting reactant is the starting material which controls the amount of product being formed.
Answer: 10
Explanation:
The detailed solution is contained in the image attached. The molar mass of hydrated and anhydrous salts are obtained and the number of moles of hydrated and hydrated salts are equated. The masses of hydrated and anhydrous salts are gives in the question and are simply substituted accordingly. This can now be used to obtain the number of molecules of water of crystallization as required in the question.
D. Ba and F. Took the test
The sun of the protons a D neutrons in the nucleus of an atom is called the ATOMIC MASS
