The reaction of sodium phosphate solution with nickel(II) perchlorate solution produces solid nickel(II) phosphate and aqueous sodium
perchlorate. Identify the spectator ions in this reaction.

The molecular equation shows each of the substances in the reaction as compounds with physical states written next to the chemical formulas. The complete ionic equation shows each of the aqueous compounds as separate ions.

Explanation:

When two solutions of ionic compounds are mixed, a solid may form. This type of reaction is called a precipitation reaction, and the solid produced in the reaction is known as the precipitate. You can predict whether a precipitate will form using a list of solubility rules such as those found in the table below. When a combination of ions is described as insoluble, a precipitate forms. There are three types of equations that are commonly written to describe a precipitation

1 a

2 d

3 a

4 c

explanation:

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.