List of practice Questions

Removel of keystone species cause serious disruption in the functioning of the community. Keystone species are low in abundance (or biomass) than the dominant species.

Which of the following compounds shows optical isomerism ?

Which of these is least likely to act as Lewis base?

Hose pipe for delivery of petrol at a petrol pump is made up of

Basic strength is maximum for

Magnesium burns in air to give

Atretic follicles are found in the

The thallus of Riccia is internally differentiated into an upper photosynthetic region and lower storage region. The lower storage region is formed from parenchymatous cells.

The ratio of inertial mass to gravitational mass is equal to one. The inertial mass and gravitational mass of a body are equivalent.

Pulmonary circulation consists of flow of deoxygenated blood from right ventricle to the lungs and flow of oxygenated blood from lungs to the left atrium. Systemic circulation consists of flow of oxygenated blood from the left ventricle to all parts of the body and deoxygenated blood from different parts to right atrium.

Placenta in addition to connection with mother and foetus to ductless gland. It releases human gonadotropins.

One codon may code for more than one amino acid. A codon is degenerate and ambiguous.

$\left[ Ni ( CO )_{4}\right]$ is a diamagnetic complex. All the electrons in the complex are paired.

$NaOH$ cannot be stored in a vessel made of aluminium or zinc. A protective layer of oxide is formed on the surface of the metal.

Monoclinic sulphur is an example of monoclinic crystal system. For a monoclinic system, $a\ne b\ne c$ and $\alpha=\gamma=90^{\circ}, \beta=90^{\circ}$.

Magnetic field interacts with a moving charge and not with a stationary charge. A moving charge produces a magnetic field.

Interspecific competition is the only potent force in organic evolution. Unexceptionally two closely related species competing for the same resources cannot co-exist indefinitely.

In a pivot joint, rounded or pointed bone fits into a shallow depression in another bone. Pivot joints are present between the metacarpals and phalanges of the fingers.

Human heart is myogenic. The contraction is initiated by a specialized patch of modified heart muscles without requiring stimulation from nerve cells.

Conductivity of all electrolytes decreases on dilution. On dilution number of ions per unit volume decreases.

Chloroform is stored in dark coloured bottles. Chronic chloroform exposure may cause damage to liver and kidneys.

$CaF _{2}$ has been given the name fluorspar. Solid $CaF _{2}$ emits light when heated.

Boron always forms covalent bond. The small size of $B ^{3+}$ favours formation of covalent bond.

$Al _{2} O _{3}$ is converted to aluminium by reduction with carbon. Carbon (graphite) has greater affinity for oxygen than $Al$.

An LPG cylinder, containing $15\, kg$ butane at $27^{\circ} C$ and $10\, atm$ pressure, is leaking. After one day, its pressure decreased to 8 atm. The quantity of gas leaked is