No, the substance like vinegar, tamarind etc. contain acids which when accidentally fall on marble will react with the marble causing discoloration etc.

(i) It is blue green
(ii) NCIOH + HCI \(\longrightarrow\) NCICI + H₂O

\(\underset{(Blue)}{CuSO_4}+Fe\longrightarrow \underset{(Green)}{FeSO_4}+Cu\)
Iron is more reactive than copper. Hence it displaces copper from copper sulphate and due to formation of FeSO₄, the colour changes from blue to green.

HCl and HNO₃ produce H⁺ in aqueous solution. Hence, they show acidic character.
Alcohol and glucose do not produce H+ in aqueous solution, hence they do not show acidic character.

B will be basic nature, with pH = 8.

Red litmus turns blue in solution of ammonium hydroxide.

The chemical formula of washing soda is \(Na_2CO_3.10H_2O.\)
Washing soda.  On heating, baking soda gives sodium carbonate, carbon dioxide and water.  Consequently, the recrystallisation of sodium carbonate gives washing soda.  The chemical equations involved in the process are:

\(\underset{Baking\ soda}{2NaHCO_3}\rightarrow \underset{Sodium\ carbonate}{Na_2CO_3}+\underset{Carbon\ dioxide}{CO_2}+\underset{Water}{H_2O}\)

\(Na_2CO_3\rightarrow10H_2O\xrightarrow {Recrystallization}\underset{Washing\ soda}{Na_2CO_3.10H_2O}\)
Washing soda is used in glass, soap and paper industries.

Egg shells contain calcium carbonate When nitric acid is added to it, carbon dioxide gas is evolved. The reaction can be given as
\(CaCO_3+2HNO_3\rightarrow Ca(NO_3)_2+H_2O+CO_2\)

(i) Alkaline medium does not allow milk to turn sour easily.
(ii) When milk is set to curd, the presence of alkali does not allow it to become acidic easily. Hence, this milk take a longer time to set as a curd.

(i) Dilute sulphuric acid + Zinç Granules \(\rightarrow\) Zinc sulphate + Hydrogen gas
H₂SO₄(aq) + Zn(s)  \(\rightarrow\) ZnSO₄ (aq) + H₂(g)
  Dilute          Granulated
(ii) Dilute hydrochloric acid + Magnesium \(\rightarrow\) Magnesium chloride + Hydrogen gas
2HCI(aq) + Mg(s) \(\rightarrow\) MgCl₂(aq) + H₂(g)
   Dilute
(iii) Dilute sulphuric acid + Aluminium \(\rightarrow\) Aluminium sulphate + Hydrogen gas
3H₂SO₄ (aq) + 2Al(s) \(\rightarrow\) Al₂(SO₄)₃(aq) + 3H₂(g)
        Dilute
(iv) Dilute hydrochloric acid + Iron \(\rightarrow\) Iron (II) chloride +Hydrogen gas
2HCI(aq)+ Fe (s) \(\rightarrow\)FeCl₂(aq)+ H₂(g)
    Dilute

CaSO₄. \(\frac{1}{2}\) H₂O (s) + 1\(\frac{1}{2}\)H₂O(l) \(\rightarrow\) CaSO₄ . 2H₂O(s)
    Plaster of Paris                                    Gypsum                            
or (CaSO₄)₂. H₂O(s) + 3H₂O(l) \(\rightarrow\) 2CaSO₄ . 2H₂O(s)

Sodium hydroxide is a strong base. When excess base is dissolved in the solution of NaOH, the concentration of hydroxide ions (OH^-) per unit volume increases due to dissociation of NaOH as well as the other base in aqueous solution.
NaOH \(\overset{H_{2}O}{\rightleftharpoons}\) Na⁺ + OH^-
Any other base
e.g. M(OH)_x \(\overset{H_{2}O}{\rightleftharpoons}\) M⁺ + xOH^-

An acid dissociates into hydronium ions (H₃O⁺) and anions when dissolved in water. When a solution is diluted, the volume of the solution increases but the number of ions remains the same, so concentration of hydronium ions (H₃O⁺) per unit volume decreases.