SAT (Stage-1) Mock Test - 75

Cl has 7 valence electrons and valency 1.
Hence this is the correct option.

Li has 1 valence electron and valency is 1.
P has 5 valence electrons and valency is 3.
Mg has 2 valence electrons and valency is 2.

The melting point decreases down a group.
Among the alkaline earth metals the decreasing order of melting points is Be, Mg, Ca, Sr, Ba.

The nucleus of every living cell contains deoxyribonucleic acid or DNA that has specific genetic information and controls every feature of the body such as colour, looks, etc.

Acidity of a base is the number of hydroxyl ions which one molecule of the base can furnish in its aqueous solution.
NaOH and NH₄OH are monobasic.
Ca(OH)₂ is dibasic.
Fe(OH)₃ is tribasic.

Sodium hydroxide is used in the production of rayon.
Rayon was the first semi-synthetic fibre obtained by treatment of wood pulp with NaOH.
It has a silk like sheen and so it became popular as artificial silk.

Only ethanoic acid will give red colour with litmus solution. Hence, it can be used for the distinction test between ethanol and ethanoic acid.

Both ethanol and ethanoic acid react with Na metal to produce a salt and hydrogen gas.

Both ethanol and ethanoic acid react with NaOH to produce a salt and water.

Both ethanol and ethanoic acid give the esterification reaction to form esters that have a sweet fruity odour.

Cell membrane consists of the lipid bilayer with embedded proteins. Hence these two are required for the structural integrity of the cell membrane.

Vacuole has single membrane, whereas nucleus, mitochondrion and chloroplasts have two membranes. Thus, 'vacuole' is the odd one.

This pair is correctly matched as Pulmonary artery carries deoxygenated blood from the right ventricle of heart towards the lungs for oxygenation.

Poikilothermic animals are cold-blooded animals in which their body temperature varies with environmental temperature. Homeothermic animals are warm-blooded animals in which temperature remains constant. Pisces and Amphibians are Poikilothermic animals & Aves and Mammals are Homeothermic animals.

Auxin is a plant hormone responsible for controlling the direction of growth of root tips and stem tips in response to different stimuli including light and gravity.

A pyramid of biomass is a graphical portrayal of biomass present in a unit of the territory of different trophic levels. In addition, it displays the linking among biomass and trophic level estimating the biomass available in each trophic degree of an energy network at a given time. The pyramid of biomass is inverted in a pond ecosystem because the biomass of fish is higher as compared to producers.

Hydrogen gas is not responsible for heating earth`s surface and atmosphere.More generally, molecules that can acquire a charge asymmetry by stretching or flexing (CO₂, H₂O, N₂O, O₃, hydrocarbons...) are greenhouse gases; molecules that cannot acquire charge asymmetry by flexing or stretching (N₂, O₂, H₂) are not greenhouse gases.

World Environment Day (WED) is celebrated annually on 5 June and is the United Nations' principal vehicle for encouraging awareness and action for the protection of the environment.
It was first held in 1974.
It has been a platform for raising awareness on environmental issue such as marine pollution, human overpopulation, global warming, sustainable consumption and wildlife crime. World Environment Day is a global platform for public outreach, with participation from over 143 countries annually.

Calcitonin polypeptide hormone is produced in humans primarily by the parafollicular cells (also known as C-cells) of the thyroid apart from thyroxine and triiodothyronine.