<span>Acid is a molecule capable of
donating hydrogen ion and they form aqueous solutions with a sour taste while
base is a substance that accepts proton from proton donor and in aqueous solution,
they have an astringent or bitter taste. Moreover, a good example for base is
sodium hydrogen carbonate as baking soda or baking powder and for acid, the
most common example is the acetic acid or vinegar.</span>
Answer:b.CaCl2
Explanation:
A compound is a substance resulting when two or more elements are are chemically bonded together either ionically or covalently in a fixed ratio.
From the given options we can see that the only compound there is CaCl2 which is an ionic compound in the fixed ratio of one calcium ion to two chloride ions.
Other options , Cu,Na and Nd are merely pure substance---Elements
Intermolecular force for solids is high. Whereas low in gases. The smell of agarbatti spreads immediately because the molecules of air diffuses very fastly.
Since obliquity is the angle between the axis of rotation and the direction perpendicular to the orbital plane, it changes as the orbital plane changes due to the influence of other planets. But the axis of rotation can also move (axial precession), due to torque exerted by the sun on a planet's equatorial bulge.
(Got it from google )
The semi will have the hardest time changing direction because of its mass. The more mass there is, the more effort it takes to accelerate and decelerate as well as change direction.
