What is Ka for HCN(aq) H+(aq)+CN-(aq)?

Further explanation  

According to Arrhenius, acids are substances which, when dissolved in water, release Hions.  

An HₓY acid in water will ionize:  

HₓY (aq) ⇒ xH⁺ (aq) + Yˣ- (aq)  

In general, the weak acid ionization reaction  

HA (aq) ⇒ H⁺ (aq) + A⁻ (aq)  

Ka's value  

So for HCN

HCN(aq)⇒H⁺(aq)+CN⁻(aq)

The metal is named first

Heat is involved in chemical change in two ways; chemical changes either result in heat being added to or removed from an object, and chemical changes require a certain amount of heat before they can take place.