NEET Practice Questions (MCQs) with Answers & Solutions

From Table 6.3, the densities are: $n-C_3H_7Cl$ (0.89 g/mL), $CH_2Cl_2$ (1.336 g/mL), $CHCl_3$ (1.489 g/mL), $CCl_4$ (1.595 g/mL). The density increases with an increase in the number of halogen atoms and the atomic mass of the halogen atoms. $CCl_4$ has the highest density among the given options (1.595 g/mL).

The NCERT text states, 'The density increases with increase in number of carbon atoms, halogen atoms and atomic mass of the halogen atoms.' Also, 'Bromo, iodo and polychloro derivatives of hydrocarbons are heavier than water.'

The NCERT states, 'Alkyl halides are colourless when pure. However, bromides and iodides develop colour when exposed to light.'

The NCERT mentions, 'Many volatile halogen compounds have sweet smell.'

The NCERT states, 'However, haloalkanes tend to dissolve in organic solvents because the new intermolecular attractions between haloalkanes and solvent molecules have much the same strength as the ones being broken in the separate haloalkane and solvent molecules.'

The context states: 'sperm formation continues even in old men, but formation of ovum ceases in women around the age of fifty years.' This directly indicates the end of the reproductive phase in females.

The text states: 'After coitus, sperms are transported to the ampulla, where the sperm fertilises the ovum leading to formation of a diploid zygote.' Additionally, one of the exercises asks 'Fertilisation takes place in _____________', implying a specific location.

The 'Fill in the blanks' section includes: '(d) Male and female gametes are _____________ (diploid/haploid)' and '(e) Zygote is _____________ (diploid/haploid)'. The formation of a diploid zygote from the fusion of gametes means the gametes must be haploid (n) and the zygote diploid (2n).

The text states: 'The presence of X or Y chromosome in the sperm determines the sex of the embryo.'.

The introductory paragraph of 'HUMAN REPRODUCTION' chapter 2 states: 'The reproductive events in humans include formation of gametes (gametogenesis)... fusion of male and female gametes (fertilisation) leading to formation of zygote. This is followed by formation and development of blastocyst and its attachment to the uterine wall (implantation), embryonic development (gestation) and delivery of the baby (parturition).'