This action was filed by Mike Wilson and a group of taxpayers of Pulaski County Special School District who have children in the Pulaski County School District against the Pulaski Association of Classroom Teachers, the collective bargaining representative of certified employees of the school district. Appellants filed a lawsuit challenging the legality of a teachers’ strike.
A teachers’ strike began on August 19, 1996. On August 23, 1996, appellants filed suit in the Pulaski County Chancery Court seeking a preliminary injunction to stop the strike. A hearing was held on August 23, 1996. The chancery court denied the preliminary injunction based upon the findings that appellants did not meet the burden of proving that a teachers’ strike was illegal and that the appellants did not meet the burden of proving irreparable harm.
On August 28, 1996, a federal district court, through its jurisdiction over Pulaski county and the teachers association in a suit regarding Pulaski County desegregation, enjoined the strike and ordered the parties to mediate. Following this order, the strike ended.
Despite the ending of the strike, appellants’ challenge the chancellor’s denial of the preliminary injunction claiming that the chancellor erred by failing to find that a teachers’ strike is illegal per se pursuant to Arkansas law and that due to this illegality, the preliminary injunction should have been ordered. As a procedural matter for granting preliminary injunctions, appellants contend that a showing of irreparable harm is not necessary in instances where an activity is illegal per se. Appellants do not challenge the finding by the chancellor that they did not prove that they had suffered irreparable harm. We do not agree with appellants’ characterization of the standard for granting preliminary injunctions and affirm the chancellor’s denial of the preliminary injunction.
Appellee challenged the jurisdiction of this court based upon the doctrine of mootness relying upon the traditional rule that this court will not render advisory opinions. It is true that *301appellants have requested an order from this court enjoining a teachers’ strike in the event that the teachers attempt to strike again in the future. This is speculative in nature, and no one knows if the teachers will ever do such. It is well settled that this court does not render advisory opinions nor answer academic questions. See, Saunders v. Neuse, 320 Ark. 547, 898 S.W.2d 43 (1995); Dougan v. Gray, 318 Ark. 6, 884 S.W.2d 239 (1994); Walker v. McCuen, 318 Ark. 508, 886 S.W.2d 577 (1994); Gladden v. Bucy, 299 Ark. 523, 772 S.W.2d 612 (1989); and Neely v. Barber, 288 Ark. 384, 706 S.W.2d 358 (1986).
Under Arkansas law, a case becomes moot when any judgment rendered would have no practical legal effect on an existing legal controversy. Dillon v. Twin City Bank, 325 Ark. 309, 924 S.W.2d 802 (1996); Arkansas Intercollegiate Conference v. Parnham, 309 Ark. 170, 828 S.W.2d 828 (1992). An exception to the mootness doctrine, however, allows review for appeals involving the public interest and the prevention of future litigation. Richie v. Board of Educ., 326 Ark. 587, 933 S.W.2d 375 (1996); Duhon v. Gravett, 302 Ark. 358, 790 S.W.2d 155 (1990). Although the teachers’ strike ended over one year ago, it is clear that the ability of public employees to withhold their services involves a question of significant public interest, the resolution of which would certainly preclude future litigation.
Appellants urge this court to recognize that it has already declared strikes by public employees to be illegal per se in Potts v. Hay, 229 Ark. 830, 318 S.W.2d (1958), and City of Ft. Smith v. No. 38, AFL-CIO, 245 Ark. 409, 433 S.W.2d 153 (1968). The right of public employees to strike was not the issue in those cases. We will note, however, that there is dicta in those cases which states that such strikes are illegal in Arkansas, but neither of these cases directly addresses the issue of whether a teachers’ strike or a strike by public employees is legal. Nevertheless, even assuming that the categorical statements in those cases about public strikes answers the illegal-strike question, appellants still cannot succeed.
An order granting or denying a preliminary injunction is within the chancery court’s discretion. McCuen v. Harris, 321 Ark. 458, 466, 902 S.W.2d 793 (1995). See also, Smith v. American *302Trucking Ass’n, 300 Ark. 594, 781 S.W.2d 3 (1989); American Trucking Ass’n v. Gray, 280 Ark. 258, 675 S.W.2d 207 (1983). We will not reverse a chancellor’s ruling on a preliminary injunction unless there has been an abuse of discretion. Smith v. American Trucking Ass’n, supra; Scrivner v. Portis Mercantile Co., 220 Ark. 814, 250 S.W.2d 119 (1952); Riggs v. Hill, 201 Ark. 206, 144 S.W.2d 26 (1940).
Arkansas Rules of Civil Procedure, Rule 65(a)(1) provides that, where a preliminary injunction is to be given without notice to the adversary of the one requesting it, it must be alleged by affidavit or verified complaint that, absent the injunction, irreparable harm will result to the appellant. Where notice is given, the rule contemplates that a hearing will be held at which such irreparable harm must be shown. The prospect of irreparable harm or lack of an otherwise adequate remedy is the foundation of the power to issue injunctive relief. See, Amalgamated Clothing v. Earle Indus., Inc., 318 Ark. 524, 886 S.W.2d 594 (1994); Paccar Financial Corp. v. Hummell, 270 Ark. 876, 878, 606 S.W.2d 384 (Ark. App. 1980). See also, Ahrent v. Sprague, 139 Ark. 416, 214 S.W. 68 (1919); Ex Parte Foster, 11 Ark. 304 (1850)
This court has previously explained the jurisdiction of equity with respect to public employees as follows:
There is no doubt but that equity will exercise jurisdiction to restrain acts or threatened acts of public corporations or of public officers, boards, or commissions which are ultra vires and beyond the scope of their authority, or which constitute a violation of their official duty, whenever the execution of such acts would cause irreparable injury to, or destroy rights and privileges of, the complainant, which are cognizable in equity, and for the protection of which we would have no adequate remedy at law.
Jensen v. Radio Broadcasting Co., Inc., 208 Ark. 517, 520, 186 S.W.2d 931, 932 (1945). Clearly, for equity to act, there must be proof of (1) irreparable harm and (2) no adequate remedy at law. See, East Poinsett Sch. Dist. No. 14 v. Massey, 317 Ark. 219, 876 S.W.2d 573 (1994).
Thus, in order for a chancellor to grant a preliminary injunction, the moving party must establish irreparable harm; this is true *303in all instances where injunctive relief is sought regardless of whether the party may additionally prove that an activity is illegal per se. In this case, appellants are precluded from establishing that the chancellor abused her discretion because they do not challenge her ruling that no irreparable harm had been suffered. Indeed, they contend that the strike was illegal per se and that this factor alone supports injunctive relief. For over a century, this court has required proof of facts establishing that the moving party is entitled to injunctive relief from a court of equity. See, e.g., Foster Ex Parte, 11 Ark. 304 (1850) (requiring proof of irreparable harm to enjoin a trespass). Appellants make no attempt to prove irreparable harm. In effect, they ask us to change this court’s longstanding posture on equity jurisdiction without the support of any convincing legal authority. Under such circumstances, this court has, and should, decline to do so. See, e.g., Qualls v. Ferritor, 329 Ark. 235, 947 S.W.2d 10 (1997); Porter v. Harshfield, 329 Ark. 130, 948 S.W.2d 83 (1997).
Because appellants failed to prove irreparable harm, we affirm the chancellor’s order.
Glaze, J., dissents.
Corbin, J., concurs in part and dissents in part.
Imber, J., not participating.
Don Donner, Special Justice, concurs in part and dissents in part.