Tag: chemistry

The solvent dissolves a large amount of solute at boiling temperature, i.e an increase in temperature increases the solubility of the solute. As the temperature increases, the particles of the solid move faster which increases the chances that they will interact more with the solvent molecules. As the temperature increases, the amount of solute that can be dissolved in a solvent increases generally is high at their individual boiling points.

Desiccators are an economical and reliable way to assure dry, dust-free storage and organization of humidity sensitive products valuable reagents in crystalline form. Proper storage conditions can be optimized by selecting a desiccator size, shape and control mechanism best suited for the application.
The lower compartment of the desiccator contains lumps of silica gel, anhydrous calcium chloride to absorb water vapor. The substance needing the desiccation is put in the upper compartment, on a glazed perforated ceramic plate. The ground glass rim of the desiccator lid must be greased with a thin layer of vacuum grease. 

Phenolphthalein [3,3-Bis (4- hydroxyphenyl)- 2 benzofuran- 1-one] is often used as an indicator in acid-base titrations. It turns colourless in acidic solutions and pink in basic solutions.

Phenolphthalein [3,3-Bis (4- hydroxyphenyl) - 2 benzofuran- 1-one] is often used as an indicator in acid-base titrations. It turns colourless in acidic solutions and pink in basic solutions. Phenolphthalein is slightly soluble in water and usually dissolved in alcohols for use in experiments. It is a weak acid which can loose $H^{+}$ ions in solution. Phenolphthalein molecule is colourless and phenolphthalein ion is pink in colour. When a base is added to phenolphthalein, the molecule turns in to ions leading to more ionization as $ H^{+} $ ions are removed.

The option (A) represents correct statements.
Salt can be obtained by the evaporation of sea water.
The salt obtained during crystallisation is not pure and its crystals are small.
After crystallisation, the shape of the crystals cannot be seen clearly.
Large crystals of pure substances can be formed from their solutions.

On evaporation of seawater in shallow pools, salt along with impurities remain behind. Impured salt is taken in a tank and its saturated solution is prepared. In a saturated solution of salt, HCl vapours are passed. Chloride ions being common to both, it's concentration increases, and NaCl gets precipitated which is free from impurities.

The process of forming large crystals of pure substances from their solutions is known as Crystallization. The principle of crystallization is concerned with the thermodynamic conditions of crystallization and the kinetics of crystal nucleation and growth.
Crystallization is the physical transformation of a liquid solution or gas to a crystal which is a solid with an ordered internal arrangement of molecules, ions or atoms.

The process of formation of solid crystals from a homogeneous solution is called crystallization. It is a physical change. Crystallization is the solidification of atoms or molecules into a highly structured form called a crystal. It can also refer to the solid-liquid separation and purification technique in which mass transfer occurs from a liquid solution to a pure solid crystalline phase.

Phenolphthalein [3,3-Bis (4- hydroxyphenyl)- 2 benzofuran- 1-one] is often used as an indicator in acid-base titrations. It turns colourless in acidic solutions and pink in basic solutions. Phenolphthalein is slightly soluble in water and usually dissolved in alcohols for use in experiments. It is a weak acid which can loose $H^{+}$ ions in solution.