Properties of Acids and Bases

Properties of Acids and Bases Acids Bases Have a sowi tasto • Hame a bitter taste change colour of many Indicators Change the colour of many indicators Are corrosive Loveact with metals) Have a slippery feeling. • neutralizesbases Neutralize acids. conduct an electric avvrent, • conduct an electric cwrrient Amphoteric substances A substance that can act as both an acid and a base is termed as Amphoteric. water is a prime example For example As a base in 20+ не но⁺ +ce- As an acid in H₂O + NH, NHA HOHF Acid, Base Theories Arvinenius Thepry gupras ban Arrhenius acid; substance which when dissolvues in wo aqueous solution yields Hydronium ions. Arrhenius base: A substance which when dissolved in aqueous solution yields Hydroxide ions. Bronsted-Lovery. Theory of Acid bases Acid: A proton donor Base: A proton acceptor Conjugate acid base pair differ by one protion. Conjugate acid is particle formed when a base goins a proton Conjugate base is a particle formet when an aci'd donates a peceton H3PO4 + NO2 HNO2 + H2PO4 Conpgate acid base conjugate acid conjugate babe - CN + HCO3 HCN acid +00 a acid conjugats conjugate. base HCN+ 5032 HSD₃ + acid base conjugate CN- conjugate base H20 base + HF acid → F conjugate base + H3O+ conjugate acid. Conjugate base:- when an acid gives off a proton a conjugate base is formed Conjugate acid:- when a base acceptsa proton a conjugate acid is formed. Conjugate acid-base pairs differ by one perston. The Lewis Theory of Acids and Basas Lewis Acid; a substance that can accept an electron pair to form a covalent bond. Lewis base: a substance that can donate an ebatron pair to form a covalent bond. Neutralization the combination of Ht with OH to form water → H+ (aq) + OH-(aq) H₂O (1) HT HARD & SOFT ACIDS AND BASES Characterstics of Hardacids * Have cations of small size Have Low polarizability * Do not possess Large no. of valence electrons *Not easily oxidized. characterstics of Hard bases Low polarizability Spread donor orbital A High electronegativity Not easily oxidised. characterstics of soft acids * High polarizability Large size Large polarizability Easily oxidised. jo wikidott Parson's HSAB principle Hard Acids prefer to bond with hard bases and soft acids profer Hard Arlds H+, Lit, Na+, k+, Rb, Cst, Be2+, Mg2+, Ca2+, Ba2+ Borderline Fe2+, Co24, Nizt, 2n2t, Pb2+ soft Cut, Ag, Au Te+, Hg, Pd2+ Cd25 Pt at Hard Bouses F,OH, HO, NH3, CO32, SO42-02- Soft Hildos bauses HR, CN, I R3P, R2S, C6H6 Note: Benzene is a soft base Applications of HSAB principle:- 1. Stability of a complex. A complex moulribe more stable if metal and ligand both are hard or soft AgIz is stable but Agh is not. doy wa rem [CoP] is more stable than [107]3- HA-HE HATSB Decurence of ores & minerals occurence of aries of certain minerals metals Can be explained on the basis of HSAB principle for example hard acid metal ions mach as Mg2+, Ca2 @cour mostly as carbonates ar halides. Poisoning of metal catalysts HSAB principle can explain the poisoning of metal catalyst. S some metals like Ni, Pt,l (soft acids) act as caralyst. These metal catalyst cante easily poisoned by substances like co, unsaturated hydrocarbons, phosphorus arsenic containing ligand poisoning is attributed to the soft acid-soft base interactions between soft metal ion andligands. Prediction of coordination in complexes of ambidentate ligands An ambidentate ligand is mone-dentats digant which can coordinato to metal ion through more than one coordinating atoms.