Which of the following substances is insoluble in water

General
1

which of the following substances is insoluble in water

2

Which of the following substances is insoluble in water?

Answer:
To determine which substances are insoluble in water, it’s essential to understand the general solubility rules and properties of various substances. Solubility in water depends on the compound’s ability to form favorable interactions with water molecules. Here’s a concise guide:

General Solubility Rules:

  1. Soluble Substances:

    • Most nitrates (NO₃⁻), acetates (CH₃COO⁻), and perchlorates (ClO₄⁻) are soluble.
    • Most salts containing alkali metal ions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺) and the ammonium ion (NH₄⁺) are soluble.
    • Most chlorides (Cl⁻), bromides (Br⁻), and iodides (I⁻) are soluble, except those of Ag⁺, Pb²⁺, and Hg₂²⁺.
    • Most sulfates (SO₄²⁻) are soluble, with exceptions like BaSO₄, PbSO₄, CaSO₄, and SrSO₄.

  2. Insoluble Substances:

    • Carbonates (CO₃²⁻), phosphates (PO₄³⁻), sulfides (S²⁻), and hydroxides (OH⁻) are generally insoluble except when paired with alkali metals and NH₄⁺.

Specific Examples of Insoluble Substances:

Based on these general rules, let’s name some commonly known substances that are insoluble in water:

  1. Barium Sulfate (BaSO₄):

    • Barium sulfate is not soluble in water.

      \text{BaSO}_4 \text{ (s)} \rightleftharpoons \text{Ba}^{2+} \text{ (aq)} + \text{SO}_4^{2-} \text{ (aq)}

    However, the equilibrium lies heavily towards the solid form, making it insoluble under standard conditions.

  2. Calcium Carbonate (CaCO₃):

    • Calcium carbonate, commonly found in chalk, limestone, and marble, is insoluble in water.

      \text{CaCO}_3 \text{ (s)} \rightleftharpoons \text{Ca}^{2+} \text{ (aq)} + \text{CO}_3^{2-} \text{ (aq)}

    Again, the solubility product (Ksp) is very low, indicating minimal solubility.

  3. Lead(II) Chloride (PbCl₂):

    • Lead(II) chloride is only slightly soluble in cold water, becoming more soluble in hot water. For the purposes of typical aqueous reactions at room temperature, it is generally considered insoluble.

      \text{PbCl}_2 \text{ (s)} \rightleftharpoons \text{Pb}^{2+} \text{ (aq)} + 2\text{Cl}^- \text{ (aq)}

Determining Insolubility:

When faced with multiple substances and tasked with determining which one is insoluble in water, use the provided solubility rules. So, if for instance, you have a list:

  • Sodium chloride (NaCl)
  • Potassium nitrate (KNO₃)
  • Calcium carbonate (CaCO₃)
  • Magnesium sulfate (MgSO₄)

Based on the solubility rules:

  • NaCl and KNO₃ are soluble.
  • MgSO₄ typically is soluble.
  • CaCO₃ is typically insoluble in water.

Final Answer:
The substance that is insoluble in water adheres to the solubility rules and examples. In the context of an example list, Calcium Carbonate (CaCO₃) is a substance that is typically insoluble in water. For any specific list provided, use the solubility rules to determine the correct answer.