Textbook Question
The atomic radii of zirconium (160 pm) and hafnium (159 pm) are nearly identical. Explain.
Ch.21 - Transition Elements and Coordination Chemistry
Chapter 21, Problem 51
Write a balanced net ionic equation for the reaction of each of the following metals with dilute sulfuric acid in the absence of air. If no reaction occurs, indicate N.R.: (a) Mn (b) Ag (c) Sc (d) Ni.
Verified step by step guidance1
Step 1: Identify the general reaction of a metal with dilute sulfuric acid. The reaction typically involves the metal reacting with sulfuric acid (H2SO4) to produce hydrogen gas (H2) and a metal sulfate (MSO4).
Step 2: Write the molecular equation for each metal reacting with sulfuric acid. For example, for manganese (Mn), the equation is: Mn + H2SO4 -> MnSO4 + H2.
Step 3: Determine the solubility of the products and dissociate any soluble ionic compounds into their constituent ions. For example, MnSO4 is soluble, so it dissociates into Mn^2+ and SO4^2- ions.
Step 4: Write the complete ionic equation by showing all the ions present in the reaction. For Mn, it would be: Mn + 2H^+ + SO4^2- -> Mn^2+ + SO4^2- + H2.
Step 5: Cancel out the spectator ions that appear on both sides of the equation to write the net ionic equation. For Mn, the net ionic equation is: Mn + 2H^+ -> Mn^2+ + H2. Repeat this process for each metal and determine if a reaction occurs.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Net Ionic Equations
A net ionic equation represents the chemical species that are involved in a reaction, excluding spectator ions. It focuses on the actual chemical change occurring in the solution, providing a clearer picture of the reaction. To write a net ionic equation, one must first write the balanced molecular equation, then dissociate the soluble ionic compounds into their ions, and finally eliminate the spectator ions.
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Reactivity of Metals
The reactivity of metals with acids varies significantly among different elements. Some metals, like zinc and magnesium, readily react with dilute acids to produce hydrogen gas, while others, such as silver and gold, do not react at all. Understanding the reactivity series of metals helps predict whether a specific metal will react with an acid and the products formed during the reaction.
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Dilute Sulfuric Acid
Dilute sulfuric acid (H2SO4) is a strong acid that can donate protons (H+) in solution, facilitating reactions with metals. In the context of metal-acid reactions, it can lead to the formation of hydrogen gas and metal sulfate salts. The concentration of the acid influences the extent of the reaction, and in some cases, certain metals may not react with dilute sulfuric acid, leading to a notation of 'N.R.' for no reaction.
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Related Practice
Textbook Question
Which of the following transition metals have more than one oxidation state?
(a) Ti
(b) V
(c) Cr
(d) Zn
Textbook Question
The highest oxidation state for the early transition metals Sc, Ti, V, Cr, and Mn is the periodic group number. The highest oxidation state for the later transition elements Fe, Co, and Ni is less than the periodic group number. Explain.