Common Chemical Compounds and Reactions

Na2CO3.10H2O is the correct formula for washing soda (sodium carbonate decahydrate). This is different from soda ash (anhydrous Na2CO3) or the monohydrate form. The 10 water molecules are chemically bound in the crystal structure, which gives washing soda its characteristic properties.

In zeolite water softening, sodium ions (Na+) from the zeolite exchange with calcium and magnesium ions (Ca2+, Mg2+) in hard water. The zeolite releases Na+ and traps Ca2+/Mg2+ ions. This process removes hardness ions that cause scaling. Option B correctly identifies Na+ and Mg2+ as involved in the exchange.

Sodium thiosulphate forms strong complex with gold ions and it is non-toxic. So, some very refractory substances in gold ore can be leached.

Sodium oxide is not present in cement at all.

Sulphur dioxide is affecting the Taj in the form of acid rain.

Crookes glass (or Crookes radiometer glass) contains cesium oxide, which gives it its distinctive yellow color and radiation-absorbing properties. It was historically used in radiology for X-ray protection.

In a study by Trevino et al, it was found that EDTA had 89% cell survival. It also had beneficial effects on pulp cells, when used as dentin conditioner.

Nitric acid is sometimes referred to as 'Aqua Fortis' in historical and industrial contexts. The term 'Aqua Gold' appears to be a confusion between 'Aqua Fortis' (strong water - nitric acid) and 'Aqua Regia' (royal water - mixture of nitric and hydrochloric acids that can dissolve gold). Among the options, nitric acid is the closest match.

Bone char is often used in sugar refining as a decolourising and deashing agent.

In glass manufacturing, soda ash (sodium carbonate) serves multiple crucial functions. One of its primary roles is to act as a flux that helps remove air bubbles from the molten glass, ensuring clarity and structural integrity. It lowers the melting temperature of silica and helps eliminate gaseous impurities that would otherwise create defects.

Non-ionic compounds are those which form covalent bonds by sharing a pair of electrons between two atoms. Water (H₂O) has a covalent bond. 

This option is correct.

Bauxite is an ore primarily composed of hydrated aluminum oxide minerals, including gibbsite (Al(OH)3), boehmite (AlO(OH)), and diaspore (AlO(OH)). The term 'hydrated aluminum oxide' accurately describes this chemical composition, making option A correct.