Chapter 4, Problem 10STP

Interpretation Introduction

Interpretation:

The missing names and formulas are to be filled

Concept introduction:

To name a compound, certain rules are followed. The given compounds are binary compounds.

Binary compounds are of three types:

• Type-I: Compound in which a metal forms ionic bond with a non-metal and the metal can form only one type of ions.
• Type-II: Compound in which a metal forms ionic bond with a non-metal and the metal can form more than one type of ions.
• Type-III: Compound in which a non-metal forms bond with a non-metal.

There is one another type of compound in which metal is bonded with a polyatomic ion

Rules for naming these compounds:

Type-I:

1. Name of metal cation is written as name of element.
2. Name of anion is written using root name and adding ‘ide’ to it.
3. Writing these names in the same sequence gives the name of compound.

Type-II:

1. Name of metal cation is written as name of element followed by charge carried by it in roman numerals in bracket.
2. Name of anion is written using root name and adding ‘ide’ to it.
3. Writing these names in the same sequence gives the name of compound.

Type-III:

1. The name of the first element is written as given in the periodic table.
2. Second element in anionic form and prefixes are used to denote the number of atoms. Like, prefix mono is not used for 1element.

When metal is bonded with polyatomic ion, rules are similar to ionic binary compounds.

Answer to Problem 10STP

Name	Formula
Barium phosphate	${\left(Ba\right)}_3{\left(P{O}_4\right)}_2$
Nitrogen(I) oxide	$N_{2}O$
Sulphuric acid	$H_{2}S{O}_4$
Copper(I) oxide	$C{u}_{2}O$
Boron trifluoride	$B{F}_3$

Explanation of Solution

Barium phosphate is a compound of metal of type-I with polyatomic ion “phosphate”. Barium ion carry +2 charge and phosphate carries -2. So , to make net charge zero three ions of barium are joined with two ions of phosphate. Therefore, correct formula is ${\left(Ba\right)}_3{\left(P{O}_4\right)}_2$

$N_{2}O$ is a binary compound of non-metal with non-metal. Oxide ion carries -2 charge so to balance charge nitrogen should be carrying +1 charge. Therefore, its name is Nitrogen(I) oxide.

Sulphuric acid is formed from sulphate ion because its name is ending with ‘ic’ and sulphate ion carries -2 charge. So, its formula is $H_{2}S{O}_4$

$C{u}_{2}O$ is a binary compound of non-metal with non-metal. Oxide ion carries -2 charge so to balance charge copper should be carrying +1 charge. Therefore, its name is Copper(I) oxide.

Boron trifluoride is a binary compound of non-metal with non-metal. So, its formula is $B{F}_3$