The temporary hardness of water is caused by the presence of: MCQ with Answer and Explanation

Explanation:
Ernest Rutherford, through the gold foil experiment in 1911, discovered the dense, positively charged nucleus. Thomson discovered the electron, Bohr proposed quantized orbits, Chadwick discovered the neutron. Rutherford also discovered the proton.

Explanation:
Soap molecules have a hydrophilic ionic head (COO⁻Na⁺) and a long hydrophobic hydrocarbon tail. In water, the tails aggregate away from water, forming a spherical micelle with heads outward. The hydrophobic core dissolves oily dirt, which is then washed away. This structure is stabilized by ion-dipole interactions. Detergents work similarly but with different head groups.

Explanation:
C₂H₄ (ethene) is an alkene with a carbon-carbon double bond, thus unsaturated. The general formula CnH₂n indicates an alkene or cycloalkane. C₃H₈, C₄H₁₀, C₅H₁₂ follow CnH₂n+2 and are saturated alkanes. Unsaturated compounds undergo addition reactions, whereas saturated undergo substitution.